cvsserver update: comment about how we shouldn't remove a user-modified file

Instead of a comment, we should really add test cases and actually fix it.

Signed-off-by: Matthew Ogilvie <mmogilvi_git@miniinfo.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-cvsserver.perl

@@ -1144,6 +1144,10 @@ sub req_update
 
         if ( $meta->{filehash} eq "deleted" )
         {
+            # TODO: If it has been modified in the sandbox, error out
+            #   with the appropriate message, rather than deleting a modified
+            #   file.
+
             my ( $filepart, $dirpart ) = filenamesplit($filename,1);
 
             $log->info("Removing '$filename' from working copy (no longer in the repo)");