Add third outcome of auth_fsm: the no_auth_info_event, which should be
dispatched when auth failed because the HLR has no auth info for this
subscriber, i.e. not because an actual auth challenge failed.
No functional change: Handling no_auth_info_event separately follows in
another patch (to allow fallback to no-auth). Feed the same
_E_AUTH_FAILURE as no_auth_info_event to still behave unchanged.
Related: OS#4830
Change-Id: I5103b1f2727f1729a5517ae359df813d50436ed3