Consolidate duplicated code in isc_socket_sendto[v] and isc_socket_recv[v].
Consolidate duplicated code in isc_socket_sendto[v] and isc_socket_recv[v].

each/bind9-collab,pecharmin/bind9,each/bind9-collab,pecharmin/bind9,each/bind9-collab,each/bind9-collab,pecharmin/bind9,pecharmin/bind9,each/bind9-collab,pecharmin/bind9,pecharmin/bind9,each/bind9-collab