builtin/grep: fix leaking object context

Even when `get_oid_with_context()` fails it may have allocated some data
in the object context. But we do not release it in git-grep(1) when the
call fails, leading to a memory leak. Plug it.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/grep.c

@@ -1133,6 +1133,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 					 &oid, &oc)) {
 			if (seen_dashdash)
 				die(_("unable to resolve revision: %s"), arg);
+			object_context_release(&oc);
 			break;
 		}
 

t/t6132-pathspec-exclude.sh

@@ -2,6 +2,7 @@
 
 test_description='test case exclude pathspec'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '

t/t6135-pathspec-with-attrs.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test labels in pathspecs'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup a tree' '