sgsn_test: guard against struct gprs_ra_id changing

sgsn_test initializes various struct gprs_ra_id without naming the actual
members, which is vulnerable to struct member re-ordering. Name the members
explicitly.

An upcoming ABI change in libosmocore would cause test failures here without
this patch.

Change-Id: I517ed9edf77fac37d9de7a39df24c419a8a65d96
1 file changed