rem: if (T==T_UNDEFINED || T==T_NULL)
add: if (T==T_UNDEFINED || T==T_NULL_CELL)
context: int t_unref( struct sip_msg* p_msg  ){	if (T==T_UNDEFINED || T==T_NULL)		return -1;	if (T->kr==0 		||(p_msg->REQ_METHOD==METHOD_ACK && !(T->kr & REQ_RLSD))) {		LOG(L_WARN, "WARNING: script writer didn't release transaction\n");		t_release_transaction(T);	}	UNREF( T );	set_t(T_UNDEFINED);	return 1;}