Changes

ttcn3-asterisk: Set mp_ims_imei matching pjsip.conf

Since recently, the testsuite validates the IMEI received at IMS Core
over REGISTER Contact header matches the one configured at Asterisk
config file.
Hence, add the same value to Asterisk_Tests.cfg so it can match the
value.

Depends: osmo-ttcn3-hacks.git Change-Id I866d89ec137d264e257b05226900b744a93c257e
Related: SYS#6877
Change-Id: Id8bb7886ffcea506348496148e17f71cef1edc90