bug#20494: 24.3; ERC floods channel with channel log

[Robin Green]

I set erc-log-insert-log-on-open to t, and ERC inserted the log files
at the end of each of its buffers. I thought this was a bit odd, but
thought nothing more of it, until I sent a message in a channel.
Unfortunately ERC interpreted me pressing enter as meaning I wanted to
send not only the message I had just typed, but also, the entire log
file, which was beneath it in the buffer!

Obviously, this bug is kind of a deal-breaker for an IRC client. I
will not be using ERC again.

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
/usr/share/emacs/24.3/etc/DEBUG.


In GNU Emacs 24.3.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.10.9)
 of 2015-04-08 on buildvm-15.phx2.fedoraproject.org
Windowing system distributor `Fedora Project', version 11.0.11404000
System Description: Fedora release 20 (Heisenbug)

Configured using:
 `configure '--build=x86_64-redhat-linux-gnu'
 '--host=x86_64-redhat-linux-gnu' '--program-prefix='
 '--disable-dependency-tracking' '--prefix=/usr' '--exec-prefix=/usr'
 '--bindir=/usr/bin' '--sbindir=/usr/sbin' '--sysconfdir=/etc'
 '--datadir=/usr/share' '--includedir=/usr/include'
 '--libdir=/usr/lib64' '--libexecdir=/usr/libexec'
 '--localstatedir=/var' '--sharedstatedir=/var/lib'
 '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--with-dbus'
 '--with-gif' '--with-jpeg' '--with-png' '--with-rsvg' '--with-tiff'
 '--with-xft' '--with-xpm' '--with-x-toolkit=gtk3' '--with-gpm=no'
 'build_alias=x86_64-redhat-linux-gnu'
 'host_alias=x86_64-redhat-linux-gnu' 'CFLAGS=-DMAIL_USE_LOCKF -O2 -g
 -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
 -fstack-protector-strong --param=ssp-buffer-size=4
 -grecord-gcc-switches -m64 -mtune=generic' 'LDFLAGS=-Wl,-z,relro ''

Important settings:
  value of $LC_CTYPE: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Scala

Minor modes in effect:
  erc-track-mode: t
  erc-track-minor-mode: t
  erc-ring-mode: t
  erc-notifications-mode: t
  erc-networks-mode: t
  erc-netsplit-mode: t
  erc-menu-mode: t
  erc-match-mode: t
  erc-log-mode: t
  erc-list-mode: t
  erc-pcomplete-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-autojoin-mode: t
  erc-smiley-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-keep-place-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  ensime-mode: t
  yas-minor-mode: t
  company-mode: t
  magit-auto-revert-mode: t
  shell-dirtrack-mode: t
  diff-auto-refine-mode: t
  desktop-save-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-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
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
/usr/share/emacs/site-lisp/camldebug hides
/usr/share/emacs/site-lisp/tuareg/camldebug

Features:
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ansi-color git-rebase-mode thingatpt git-commit-mode log-edit easy-mmode
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hashtable-print-readable backquote make-network-process dbusbind
dynamic-setting system-font-setting font-render-setting move-toolbar gtk
x-toolkit x multi-tty emacs)