bug#17970: log-edit creates unwanted ChangeLog buffers

[Glenn Morris]

Stefan Monnier wrote:

>> What if I already did "C-x 4 a", which visited a non-existing
>> ChangeLog, and wrote my entry, but didn't yet save that buffer?

Then you get punished for not committing your ChangeLog at the same time
as the associated commit. ;)

> I guess that would make sense, indeed.  Could you refine my patch so
> as to handle that case?

(or (find-buffer-visiting changelog-file-name)
    (file-exists-p changelog-file-name))