don't print "osmo-ortp(): network_error" messages between CRCX and MDCX.
Right now we receive the messages between the IPAC_CRCX and the IPAC_MDCX. In the time in between, the stack attempts
to send RTP/UDP messages to an unknown / non-existant UDP port (portnumber 0):
<0000> rsl.c:1266 (bts=0,trx=0,ts=1,ss=0) RSL Tx IPAC_CRCX_ACK (local 127.0.0.1:61008, remote 127.0.0.1:0)
Once the MDCX is received to set the remote UDP port, the messages disappear.
We should find a way to either not send any packets until the port number is !=, or to suppress the error messages, as they confuse the user.