fsck: notice .git case-insensitively

We complain about ".git" in a tree because it cannot be
loaded into the index or checked out. Since we now also
reject ".GIT" case-insensitively, fsck should notice the
same, so that errors do not propagate.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fsck.c

@@ -175,7 +175,7 @@ static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
 			has_dot = 1;
 		if (!strcmp(name, ".."))
 			has_dotdot = 1;
-		if (!strcmp(name, ".git"))
+		if (!strcasecmp(name, ".git"))
 			has_dotgit = 1;
 		has_zero_pad |= *(char *)desc.buffer == '0';
 		update_tree_entry(&desc);

t/t1450-fsck.sh

@@ -263,6 +263,7 @@ done <<-\EOF
 dot .
 dotdot ..
 dotgit .git
+dotgit-case .GIT
 EOF
 
 test_done