modules/tm: load_contacts() now prefers contacts whose path is empty

- For contacts with the same q, order contacts so that contacts that
  have empty path are preferred over ones that have path defined.  In
  practice, this affects only contacts with the same ua instance id.

modules/tm/t_serial.c

@@ -251,7 +251,9 @@ int t_load_contacts(struct sip_msg* msg, char* key, char* value)
 
 	prev = (struct contact *)0;
 	curr = contacts;
-	while (curr && (curr->q < branch->q)) {
+	while (curr && 
+	       ((curr->q < next->q) ||
+		((curr->q == next->q) && (next->path.len == 0)))) {
 	    prev = curr;
 	    curr = curr->next;
 	}