Merge branch 'jk/leakfix'

Code clean-up.

* jk/leakfix:
  submodule--helper: fix leak of core.worktree value
  config: fix leak in git_config_get_expiry_in_days()
  config: drop git_config_get_string_const()
  config: fix leaks from git_config_get_string_const()
  checkout: fix leak of non-existent branch names
  submodule--helper: use strbuf_release() to free strbufs
  clear_pattern_list(): clear embedded hashmaps

t/helper/test-config.c

@@ -126,7 +126,7 @@ int cmd__config(int argc, const char **argv)
 			goto exit1;
 		}
 	} else if (argc == 3 && !strcmp(argv[1], "get_string")) {
-		if (!git_config_get_string_const(argv[2], &v)) {
+		if (!git_config_get_string_tmp(argv[2], &v)) {
 			printf("%s\n", v);
 			goto exit0;
 		} else {