PCU_Tests: add an IMSI when sending data via BSSGP

In many of our tests we trigger a paging by the PCU by sending some data
through BSSGP. However, we often do this without putting an IMSI into
the ts_BSSGP_DL_UD template. The PCU then send the paging through the
AGCH because without IMSI no paging group can be calculated. The tests
still expect the paging to appear on the PCH and fail.

Let's fix this by adding an IMSI to the BSSGP request so that the PCU
knows the and the paging is sent through the PCU.

Change-Id: I7a70cc2a8af9d088071841861a8120afb9af86f9
1 file changed