tm: remove unnecessary TMCB_ACK_NEG_IN callback call

	- TMCB_ACK_NEG_IN was called in an if branch where the initial
condition was the message to be an INVITE; this was not affecting
anything for the moment since this callback wasn't used but in case
some piece of code would have used this callback it would be called
not only for hop-by-hop ACKs but also INVITEs

Closes #1871

src/modules/tm/t_reply.c

@@ -2303,14 +2303,6 @@ int reply_received( struct sip_msg  *p_msg )
 									t, &onsend_params);
 						}
 					}
-					if (unlikely(has_tran_tmcbs(t, TMCB_ACK_NEG_IN))){
-						INIT_TMCB_ONSEND_PARAMS(onsend_params,
-								t->uas.request, p_msg, &uac->request,
-								&uac->request.dst, ack, ack_len,
-								TMCB_LOCAL_F, branch, TYPE_LOCAL_ACK);
-						run_trans_callbacks_off_params(TMCB_ACK_NEG_IN,
-								t, &onsend_params);
-					}
 					shm_free(ack);
 				}
 			} else if (is_local(t) /*&& 200 <= msg_status < 300*/) {