The BSC's VTY port will be used to trigger manual handover, and to
retrieve a list of active lchans from the BSC, in the upcoming
handover_2G test suite, I0b2671304165a1aaae2b386af46fbd8b098e3bd8.
Change-Id: I06652db04fc9e48748f3c2196334f5352e9cc48a
To trigger manual handovers, I need a VTY interface. The non-trivial
parts of this are copied from osmo-python-tests osmo_interact_vty.py.
Will be used in the upcoming handover_2G test suite in
I0b2671304165a1aaae2b386af46fbd8b098e3bd8.
Change-Id: I7c17b143b7c690b8c4105ee7c6272670046fa91d
Neels Hofmeyr