t7201.24: Add refspec to keep --track working

We are formalizing a requirement that any remote-tracking branch to be used
as an upstream (i.e. as an argument to --track), _must_ "belong" to a
configured remote by being matched by the "dst" side of a fetch refspec.

Without this patch, this test would start failing when the new behavior is
introduced.

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

t/t7201-co.sh

@@ -431,6 +431,7 @@ test_expect_success 'detach a symbolic link HEAD' '
 
 test_expect_success \
     'checkout with --track fakes a sensible -b <name>' '
+    git config remote.origin.fetch "+refs/heads/*:refs/remotes/origin/*" &&
     git update-ref refs/remotes/origin/koala/bear renamer &&
 
     git checkout --track origin/koala/bear &&