MERGE_RR is in .git, not .git/rr-cache

0af0ac7 (Move MERGE_RR from .git/rr-cache/ into .git/) moved the
location of MERGE_RR but I found a few references to the old
location.

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/rerere.c

@@ -135,7 +135,7 @@ int cmd_rerere(int argc, const char **argv, const char *prefix)
 			if (!has_rerere_resolution(name))
 				unlink_rr_item(name);
 		}
-		unlink_or_warn(git_path("rr-cache/MERGE_RR"));
+		unlink_or_warn(git_path("MERGE_RR"));
 	} else if (!strcmp(argv[1], "gc"))
 		garbage_collect(&merge_rr);
 	else if (!strcmp(argv[1], "status"))

t/t4151-am-abort.sh

@@ -47,7 +47,7 @@ do
 		test_must_fail git am$with3 --skip >output &&
 		test "$(grep "^Applying" output)" = "Applying: 6" &&
 		test_cmp file-2-expect file-2 &&
-		test ! -f .git/rr-cache/MERGE_RR
+		test ! -f .git/MERGE_RR
 	'
 
 	test_expect_success "am --abort goes back after failed am$with3" '
@@ -57,7 +57,7 @@ do
 		test_cmp expect actual &&
 		test_cmp file-2-expect file-2 &&
 		git diff-index --exit-code --cached HEAD &&
-		test ! -f .git/rr-cache/MERGE_RR
+		test ! -f .git/MERGE_RR
 	'
 
 done