propagate RSL error cause codes to RR Channel Release cause

In various places that receive an error cause from RSL and place it in
lchan.release.rsl_error_cause, translate it to an RR cause and place that in
the recently added lchan.release.rr_cause. Hence the RR Channel Release message
now reflects more specific error causes when the reason for the error was
received in an RSL message's cause value.

Change-Id: I46eb12c91a8c08162b43dd22c7ba825ef3bbc6ac
4 files changed