Filtering by IMSI in osmo-bsc is a legacy use case with questionable
usefulness. Remove.
Do not keep deprecated VTY commands: those could be dangerous, since
(presumably non-existing) users might assume that the filtering would still be
in place. Rather fail to start osmo-bsc for config with an IMSI ACL.
The IMSI filtering did, if present, provide the logging with an IMSI to print
for the bsc_subscriber. TMSIs should have ended up in logging likewise, which
has never been implemented. The proper way to learn the IMSI would be by the
Common Id message from the MSC. Furthermore, the upcoming MSC pooling feature
will extract the mobile identity again, and will hence make sure that both IMSI
and TMSI identities, as available, end up in the bsc_subscriber and will be
logged again.
So long, IMSI ACL, and thanks for all the fish.
Change-Id: I89727af5387e8360362e995fdee959883c37d89a
5cda1d01b4