bug#21384: 25.0.50; vc-next-action (RCS) backend gives error.

[Eli Zaretskii]

> From: Uwe Brauer <oub@mat.ucm.es>
> Date: Mon, 31 Aug 2015 10:54:30 +0000
> 
> In GNU emacs 21.4.5 I can use vc-next-action for a file which is under
> RCS version control without problems. In 25.0.50.1 I obtain an error
> which I attach.
> [...]
>
> Debugger entered--Lisp error: (void-variable add-log-time-zone-rule)
>   log-edit-changelog-ours-p()
>   log-edit-changelog-entries("section-0006.tex")

add-log-time-zone-rule is defined in add-log.el, which you have
shadowed:

> /home/oub/emacs/site-lisp/versch/add-log hides 
> /opt/emacs25/share/emacs/25.0.50/lisp/vc/add-log

So my crystal ball says this is a cockpit error.