bts/oml: Repurpose test TC_ipa_rsl_connect_nack

The old test was not really correct, since it is fine for the BTS to ACK
the RSL CONNECT despite later on failing to connect the RSL link.
RSL_CONNECT is really just setting the attributes (it could even be
replaced by SETATTR in the future), and connect happens later on.
This can still be found out by the BSC because the BBTRANSC will never
transition to a Enabled state until the RSL link becomes up.

This patch repurposes the existent test to do some more meaningful check
in a case the RSL CONNECT can be answered with a NACK. This scenario was
actually failing to be properly checked in osmo-bts until recently, so
it is expected that it will fail (and even crash) older versions of
osmo-bts.

Depends: osmo-bts.git Change-Id If27639ae1727fc5232e1a964a1b29f50c8805d80
Related: OS#5964
Change-Id: I10df611f0086d34a5482f7c8a79703938313ab3d
2 files changed