fsck: detect more in-tree d/f conflicts

If the conflict candidate file name from the top of the stack is not a
prefix of the current candiate directory then we can discard it as no
matching directory can come up later.  But we are not done checking the
candidate directory -- the stack might still hold a matching file name,
so stay in the loop and check the next candidate file name.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fsck.c

@@ -620,7 +620,7 @@ static int verify_ordered(unsigned mode1, const char *name1,
 			if (!f_name)
 				break;
 			if (!skip_prefix(name2, f_name, &p))
-				break;
+				continue;
 			if (!*p)
 				return TREE_HAS_DUPS;
 			if (is_less_than_slash(*p)) {

t/t1450-fsck.sh

@@ -261,7 +261,7 @@ check_duplicate_names () {
 
 check_duplicate_names success x x.1 x/
 check_duplicate_names success x x.1.2 x.1/ x/
-check_duplicate_names failure x x.1 x.1.2 x/
+check_duplicate_names success x x.1 x.1.2 x/
 
 test_expect_success 'unparseable tree object' '
 	test_oid_cache <<-\EOF &&