scripts: commit-msg: tweak 72-column test to avoid a false-positive

* scripts/git-hooks/commit-msg: Don't warn about a line that is
longer than 72 if it is a comment.  Git-generated comments would
occasionally trigger this.

scripts/git-hooks/commit-msg

@@ -101,7 +101,7 @@ sub check_msg($$)
   # Limit line length to allow for the ChangeLog's leading TAB.
   foreach my $line (@line)
     {
-      72 < length $line
+      72 < length $line && $line =~ /^[^#]/
         and return 'line longer than 72';
     }