sgsn: delay f_gmm_attach() by 50ms

Packets sent by f_gmm_attach() might take too long via layers to reach
the SGSN. The GMM_ATTACH_COMPL in f_gmm_attach() took soo long,
that it arrived after packets, which has been sent after calling f_gmm_attach().
This behaviour was found in TC hlr_location_cancel_request_update().

Change-Id: I0209c86e16fe616284d753e9e003f2e4d9ec9ea5
1 file changed