t9500: write "extensions.refstorage" into config

In t9500 we're writing a custom configuration that sets up gitweb. This
requires us to manually ensure that the repository format is configured
as required, including both the repository format version and
extensions. With the introduction of the "extensions.refStorage"
extension we need to update the test to also write this new one.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

t/t9500-gitweb-standalone-no-errors.sh

@@ -627,6 +627,7 @@ test_expect_success \
 test_expect_success 'setup' '
 	version=$(git config core.repositoryformatversion) &&
 	algo=$(test_might_fail git config extensions.objectformat) &&
+	refstorage=$(test_might_fail git config extensions.refstorage) &&
 	cat >.git/config <<-\EOF &&
 	# testing noval and alternate separator
 	[gitweb]
@@ -637,6 +638,10 @@ test_expect_success 'setup' '
 	if test -n "$algo"
 	then
 		git config extensions.objectformat "$algo"
+	fi &&
+	if test -n "$refstorage"
+	then
+		git config extensions.refstorage "$refstorage"
 	fi
 '