Revert "F1AP SCTP: don't bind local address"

This reverts commit 28411652.

The problem is that (1) we don't really support multi-homing, but (2) on
some system, if the other IP addresses that the operating system
considers part of the multi-homed connection are HEARTBEAT'ed (e.g.,
docker), they answer with SCTP ABORT, which breaks the entire
connection.

In other words, force single-homing by binding. For F1-U uses, another
option will be introduced that allows to bind to a separate interface
for F1-U (separate from F1-C), if necessary.

Closes #727

openair2/F1AP/f1ap_du_task.c

@@ -64,6 +64,8 @@ void du_task_send_sctp_association_req(instance_t instance, f1ap_net_config_t *n
   sctp_new_association_req_p->out_streams = 2; //du_inst->sctp_out_streams;
   // remote
   memcpy(&sctp_new_association_req_p->remote_address, &nc->CU_f1_ip_address, sizeof(nc->CU_f1_ip_address));
+  // local
+  memcpy(&sctp_new_association_req_p->local_address, &nc->DU_f1_ip_address, sizeof(nc->DU_f1_ip_address));
   // du_f1ap_register_to_sctp
   itti_send_msg_to_task(TASK_SCTP, instance, message_p);
 }