use mgcp-client configured endpoint domain name

Rationale: reading pcaps becomes so much easier when each of osmo-bsc and
osmo-msc address their MGW with differing domain names. Otherwise, both will
have a '0@mgw' endpoint and it gets really confusing.

After this, with according configuration, there can be a '0@bsc' and a '0@msc'
endpoint.

osmo-mgw-for-msc.cfg:
 mgcp
  domain msc

osmo-msc.cfg:
 msc
  mgw endpoint-domain msc

Depends: Ia662016f29dd8727d9c4626d726729641e21e1f8 (osmo-mgw)
Change-Id: I87ac11847d1a6d165ee9a2b5d8a4978e7ac73433
1 file changed