Add tests for OS#2714, "close RSL connections from unknown Unit ID".

This adds two new tests: One for RSL, and a second one which performs
the same test on the OML port. Both tests open an IPA connection and
send a unit ID which is unknown to the BSC. The tests expect the BSC
to close the connection immediately.

We need to add handling for a socket error in IPA_Emulation because
otherwise these tests do not pass reliably as some closed connections
are not properly detected.

Change-Id: I6a947d7411a016e4d7650031396cae3575756453
2 files changed