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/t7500-commit-template-squash-signoff.sh

@@ -382,13 +382,4 @@ test_expect_success 'check commit with unstaged rename and copy' '
 	)
 '
 
-test_expect_success 'commit without staging files fails and displays hints' '
-	echo "initial" >file &&
-	git add file &&
-	git commit -m initial &&
-	echo "changes" >>file &&
-	test_must_fail git commit -m update >actual &&
-	test_i18ngrep "no changes added to commit (use \"git add\" and/or \"git commit -a\")" actual
-'
-
 test_done