Fix t5516 on cygwin: it does not like double slashes at the beginning…

… of a path

The double slashes "//" result from url./$TRASH/. expansion and the
current directory, which even in cygwin contains "/" as first
character. In cygwin such strings have special meaning: UNC path.
Accessing an UNC path built for test purpose usually fails.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5516-fetch-push.sh

@@ -146,7 +146,7 @@ test_expect_success 'push with wildcard' '
 test_expect_success 'push with insteadOf' '
 	mk_empty &&
 	TRASH="$(pwd)/" &&
-	git config "url./$TRASH/.insteadOf" trash/ &&
+	git config "url.$TRASH.insteadOf" trash/ &&
 	git push trash/testrepo refs/heads/master:refs/remotes/origin/master &&
 	(
 		cd testrepo &&