library/RSL_Emulation: optional IPA stream ID patching

Unfortunately, the latest release of osmo-bts still has a bug,
that has been fixed [1] in the recent master. Because of that,
most of the test cases in ttcn3-bts-test-latest currently fail.

The problem is that all transceivers use IPAC_PROTO_RSL_TRX0,
regardless of what the BSC tells them to use. Let's work this
around by patching IPA stream ID in ASP_RSL_Unitdata messages
coming from the IPA emulation.

[1] I5927f59a49724170a63e87be604973f7c9d5d8be

Change-Id: I66cecc9ea24ba79e1a03492e3fda2874951d37a0
1 file changed