zsh_completion: complete all files for `commit/backout --logfile`

Up until now commit/backout `--logfile` option was completed only with
*.txt-files. This requirement is a bit too strong (and is nowhere to be stated)
so it's better to complete with all files.

Stolen from zsh.git repo, c5fce37b changeset by Oliver Kiddle.

contrib/zsh_completion

@@ -497,7 +497,7 b' typeset -A _hg_cmd_globals'
     '(--user -u)'{-u+,--user}'[record user as commiter]:user:' \
     '(--rev -r)'{-r+,--rev}'[revision]:revision:_hg_labels' \
     '(--message -m)'{-m+,--message}'[use <text> as commit message]:text:' \
-    '(--logfile -l)'{-l+,--logfile}'[read commit message from <file>]:log file:_files -g \*.txt'
+    '(--logfile -l)'{-l+,--logfile}'[read commit message from <file>]:log file:_files'
 }
 
 _hg_cmd_bisect() {
@@ -565,7 +565,7 b' typeset -A _hg_cmd_globals'
   _arguments -s -w : $_hg_global_opts $_hg_pat_opts $_hg_subrepos_opts \
   '(--addremove -A)'{-A,--addremove}'[mark new/missing files as added/removed before committing]' \
   '(--message -m)'{-m+,--message}'[use <text> as commit message]:text:' \
-  '(--logfile -l)'{-l+,--logfile}'[read commit message from <file>]:log file:_files -g \*.txt' \
+  '(--logfile -l)'{-l+,--logfile}'[read commit message from <file>]:log file:_files' \
   '(--date -d)'{-d+,--date}'[record datecode as commit date]:date code:' \
   '(--user -u)'{-u+,--user}'[record user as commiter]:user:' \
   '--amend[amend the parent of the working dir]' \