usrloc: copy server_id when updating contact in memory

(cherry picked from commit 282cb4395b5c31476f97a168f509b2904727e88a)

src/modules/usrloc/ucontact.c

@@ -308,6 +308,7 @@ int mem_update_ucontact(ucontact_t* _c, ucontact_info_t* _ci)
 	_c->last_keepalive = _ci->last_modified;
 	_c->flags = _ci->flags;
 	_c->cflags = _ci->cflags;
+	_c->server_id = _ci->server_id;
 	_c->tcpconn_id = _ci->tcpconn_id;
 
 	return 0;