protocol: allow wildcarded DLCX

In many cases it is simpler to instruct the mgcp-gw to drop all
connections at once instead of removing each connection
individually.

drop all connections and release the endpoint in when no connection
id is supplied with the DLCX command.

Change-Id: Ib5fcc72775bf72b489ff79ade36fb345d8d20736
1 file changed