revert(3p/git): Revert merge of git upstream at v2.26.2

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232, reversing
changes made to f2b211131f.

third_party/git/t/t5509-fetch-push-namespaces.sh

@@ -20,7 +20,7 @@ test_expect_success setup '
 	) &&
 	commit0=$(cd original && git rev-parse HEAD^) &&
 	commit1=$(cd original && git rev-parse HEAD) &&
-	git init --bare pushee &&
+	git init pushee &&
 	git init puller
 '
 
@@ -152,15 +152,4 @@ test_expect_success 'clone chooses correct HEAD (v2)' '
 	test_cmp expect actual
 '
 
-test_expect_success 'denyCurrentBranch and unborn branch with ref namespace' '
-	(
-		cd original &&
-		git init unborn &&
-		git remote add unborn-namespaced "ext::git --namespace=namespace %s unborn" &&
-		test_must_fail git push unborn-namespaced HEAD:master &&
-		git -C unborn config receive.denyCurrentBranch updateInstead &&
-		git push unborn-namespaced HEAD:master
-	)
-'
-
 test_done