t3200: Minor fix when preparing for tracking failure

t3200: Minor fix when preparing for tracking failure

We're testing that trying to --track a ref that is not covered by any remote
refspec should fail. For that, we want to have refs/remotes/local/master
present, but we also want the remote.local.fetch refspec to NOT match
refs/remotes/local/master (so that the tracking setup will fail, as intended).
However, when doing "git fetch local" to ensure the existence of
refs/remotes/local/master, we must not already have changed remote.local.fetch
so as to cause refs/remotes/local/master not to be fetched. Therefore, set
remote.local.fetch to refs/heads/*:refs/remotes/local/* BEFORE we fetch, and
then reset it to refs/heads/s:refs/remotes/local/s AFTER we have fetched
(but before we test --track).

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>