remote: fix leaking tracking refs

When computing the remote tracking ref we cause two memory leaks:

  - We leak when `remote_tracking()` fails.

  - We leak when the call to `remote_tracking()` succeeds and sets
    `ref->tracking_ref()`.

Fix both of these leaks.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

remote.c

@@ -1097,6 +1097,7 @@ void free_one_ref(struct ref *ref)
 		return;
 	free_one_ref(ref->peer_ref);
 	free(ref->remote_status);
+	free(ref->tracking_ref);
 	free(ref->symref);
 	free(ref);
 }
@@ -2577,8 +2578,10 @@ static int remote_tracking(struct remote *remote, const char *refname,
 	dst = apply_refspecs(&remote->fetch, refname);
 	if (!dst)
 		return -1; /* no tracking ref for refname at remote */
-	if (refs_read_ref(get_main_ref_store(the_repository), dst, oid))
+	if (refs_read_ref(get_main_ref_store(the_repository), dst, oid)) {
+		free(dst);
 		return -1; /* we know what the tracking ref is but we cannot read it */
+	}
 
 	*dst_refname = dst;
 	return 0;