t1517: add missing LIBCURL prereq

After building Git with NO_LIBCURL, there is no `git remote-http`, so
it's not meaningful to test that it can run outside of a repository.
Indeed, that test will fail. Add the LIBCURL prereq to it.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1517-outside-repo.sh

diff --git a/t/t1517-outside-repo.sh b/t/t1517-outside-repo.sh
index 990a036..342defb 100755
--- a/t/t1517-outside-repo.sh
+++ b/t/t1517-outside-repo.sh
@@ -98,7 +98,7 @@
 	nongit git stripspace -s </dev/null
 '
 
-test_expect_success 'remote-http outside repository' '
+test_expect_success LIBCURL 'remote-http outside repository' '
 	test_must_fail git remote-http 2>actual &&
 	test_grep "^error: remote-curl" actual &&
 	(