git-send-pack: Fix duplicate refname match
git-send-pack: Fix duplicate refname match

Cut-and-paste dup noticed by Junio.  It's not even harmless, since a
match also causes that match to be invalidated, so this made it
impossible to update an existing branch by name.

I'd only tested the case of "ref doesn't exist at all on the other end",
which worked fine.

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git