trim_common_tail bug?

[Jeff King <peff@peff.net>]

Something seems to be not quite right with the trim_common_tail code in
xdiff-interface.c. The diff I just sent for contrib/completion looks
fine (as I sent it) when I comment out trim_common_tail. But using
the current master, it looks like this:

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 58e0e53..2fd32db 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -291,7 +291,7 @@ __git_commands ()
 	for i in $(git help -a|egrep '^ ')
 	do
 		case $i in
-		add--interactive) : plumbing;;
+		*--*)             : plumbing pattern;;
 		applymbox)        : ask gittus;;
 		applypatch)       : ask gittus;;
 		archimport)       : import;;
@@ -307,5 +307,4 @@ __git_commands ()
 		diff-index)       : plumbing;;
 		diff-tree)        : plumbing;;
 		fast-import)      : import;;
-		fsck-objects)     : plumbing;;
-		fetch--tool)      : plumbing;;
\ No newline at end of file
+		fsck-objects)     : plumbing;;
\ No newline at end of file

-Peff