t5512: run git fetch inside test

Do the preparatory fetch inside the test of ls-remote --symref to avoid
cluttering the test output and to be able to catch unexpected fetch
failures.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5512-ls-remote.sh

@@ -206,8 +206,8 @@ test_expect_success 'overrides work between mixed transfer/upload-pack hideRefs'
 	grep refs/tags/magic actual
 '
 
-git fetch origin
 test_expect_success 'ls-remote --symref' '
+	git fetch origin &&
 	cat >expect <<-EOF &&
 	ref: refs/heads/master	HEAD
 	$(git rev-parse HEAD)	HEAD