media: factor out common stream initialization
media: use TCP-PASS ports in place of zeros in TCP-ACT

TCP-active candidates libnice provides us with have port and rport
values set to zero as mandated by ICE-TCP RFC. However, some Lync
clients regard SDP requests with zero-port candidates as invalid.
For each active candidate, we have to copy the port number from its
corresponding TCP-passive counterpart.
media: removed call_hangup_cb

Already handled in sipe_media_call_free().