bug#28332: 26.0.50; vc-svn: calling revert-buffer multiple causes scrolling of buffer

[Alfred M. Szmidt]

When in vc-dired, with a relativley long list of files, and one issues
'g' (revert-buffer) the buffer scrolls downwards until the pointer
hits the bottem and then recenters.


In GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, Xaw scroll bars)
 of 2017-07-14 built on carbonium
Repository revision: 3bdf5b21493828bb0e8c0c6b4559a89aade0357f
Windowing system distributor 'The X.Org Foundation', version 11.0.11604000
System Description:     Debian GNU/Linux 8.8 (jessie)

Recent messages:
Added to /home/ams/GNU/savannah.xmail
Computing summary lines...done
Added to /home/ams/RMAIL.inbox
Mark set
vc-dir-refresh: Another update process is in progress, cannot run two at a time 
[27 times]
Type "q" in help window to restore its previous buffer.

Quit [2 times]
delete-forward-char: End of buffer
Making completion list... [2 times]

Configured using:
 'configure --with-gif=no --with-tiff=no --with-gnutls=no'

Configured features:
XPM JPEG PNG SOUND DBUS GSETTINGS NOTIFY FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS LUCID X11

Important settings:
  value of $LC_ALL: en_US.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: VC dir

Minor modes in effect:
  vc-parent-buffer: *vc-dir*
  shell-dirtrack-mode: t
  diff-auto-refine-mode: t
  rcirc-track-minor-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Load-path shadows:
~/loaddefs hides /home/ams/emacs/lisp/loaddefs
~/misc hides /home/ams/emacs/lisp/misc

Features:
(shadow emacsbug vc-filewise ld-script thai-util thai-word vc-mtn
vc-hg vc-bzr vc-src vc-sccs files-x tramp-sh man calc calc-loaddefs
tramp-smb tramp-cache cl-indent sh-script executable wdired tar-mode
calc-macs nroff-mode view texinfo vc-annotate cal-move macros tmm
rmailkwd reposition bug-reference face-remap debug rmailedit gnus-fun
rect dabbrev info two-column iso-transl cl-print eieio-opt speedbar
sb-image ezimage dframe cus-start cus-load quail gnus-html url-cache
pcmpl-gnu log-view mailalias skeleton ibuf-ext ibuffer
ibuffer-loaddefs tabify whitespace flow-fill mm-archive smiley
gnus-cite mail-extr gnus-bcklg vc-git make-mode repeat conf-mode sort
help-fns cursor-sensor mhtml-mode css-mode smie color eww mm-url
url-queue url url-proxy url-privacy url-expand url-methods url-history
url-cookie url-domsuf url-util shr svg xml js json map imenu flyspell
ispell novice org-rmail org-mhe org-irc org-info org-gnus org-docview
org-bibtex bibtex org-bbdb org-w3m org-element avl-tree org org-macro
org-footnote org-pcomplete org-list org-faces org-entities org-version
ob-emacs-lisp ob ob-tangle org-src ob-ref ob-lob ob-table ob-keys
ob-exp ob-comint tramp tramp-compat tramp-loaddefs trampver
ucs-normalize ob-core ob-eval org-compat org-macs org-loaddefs
find-func cal-menu calendar cal-loaddefs log-edit pcvs-util add-log
tcl smerge-mode shell grep doc-view jka-compr image-mode diff-mode
vc-cvs vc-rcs vc-dir ewoc vc verilog-mode diff cc-mode cc-fonts
cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs
asm-mode gnus-async gnus-ml nndraft nnmh nnfolder gnus-agent gnus-srvr
gnus-score score-mode nnvirtual gnus-msg gnus-art mm-uu mml2015
mm-view mml-smime smime dig mailcap nntp gnus-cache gnus-sum
gnus-group gnus-undo gnus-start gnus-cloud nnimap nnmail mail-source
utf7 netrc nnoo parse-time gnus-spec gnus-int gnus-range gnus-win gnus
nnheader wid-edit rng-xsd xsd-regexp rng-cmpct rng-nxml rng-valid
rng-loc rng-uri rng-parse nxml-parse rng-match rng-dt rng-util
rng-pttrn nxml-ns nxml-mode nxml-outln nxml-rap sgml-mode dom
nxml-util nxml-enc xmltok misearch multi-isearch dired-aux pcmpl-unix
network-stream nsm starttls tls gnutls rmailout rmailsum qp rmailmm
message subr-x puny dired dired-loaddefs format-spec rfc822 mml
mml-sec epa epg gnus-util mm-decode mm-bodies mm-encode mailabbrev
gmm-utils mailheader mail-parse rfc2231 rmail rmail-loaddefs em-unix
em-term term disp-table ehelp em-script em-prompt em-ls em-hist
em-pred em-glob em-dirs em-cmpl em-basic em-banner em-alias pcomplete
esh-var esh-io esh-cmd esh-opt esh-ext esh-proc esh-arg esh-groups
eshell esh-module esh-mode esh-util rcirc mail-queue sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils slime-fancy
slime-trace-dialog slime-fontifying-fu slime-package-fu
slime-references slime-compiler-notes-tree slime-scratch
slime-presentations advice bridge slime-macrostep macrostep
slime-mdot-fu slime-enclosing-context slime-fuzzy slime-fancy-trace
slime-fancy-inspector slime-c-p-c slime-editing-commands slime-autodoc
slime-repl elp slime-parse slime derived cl-extra help-mode edmacro
kmacro gud apropos compile etags xref project arc-mode archive-mode
noutline outline easy-mmode pp comint ansi-color ring hyperspec
thingatpt browse-url slime-autoloads vc-dispatcher vc-svn autoload
radix-tree lisp-mnt cl finder-inf package easymenu epg-config
url-handlers url-parse auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache url-vars seq byte-opt gv bytecomp
byte-compile cconv cl-loaddefs cl-lib time-date mule-util tooltip
eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow
isearch timer select scroll-bar mouse jit-lock font-lock syntax
facemenu font-core term/tty-colors frame cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese composite charscript charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray
minibuffer cl-preloaded nadvice loaddefs button faces cus-face
macroexp files text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget hashtable-print-readable backquote
dbusbind inotify dynamic-setting system-font-setting
font-render-setting x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 1464115 339627)
 (symbols 48 70102 282)
 (miscs 40 8195 13270)
 (strings 32 187266 40522)
 (string-bytes 1 5756641)
 (vectors 16 92197)
 (vector-slots 8 2263054 117660)
 (floats 8 561 1717)
 (intervals 56 114650 33871)
 (buffers 976 174)
 (heap 1024 268043 224730))