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
diff --git a/sgsn/SGSN_Tests.ttcn b/sgsn/SGSN_Tests.ttcn
index 281dcc9..a89a949 100644
--- a/sgsn/SGSN_Tests.ttcn
+++ b/sgsn/SGSN_Tests.ttcn
@@ -784,6 +784,14 @@
 	if (is_iu(ran_index)) {
 		as_iu_release_compl_disc();
 	}
+
+	/* Race condition
+	 * It has shown, that GMM_ATTACH_COMPL might take some time to arrive at the SGSN through the layers.
+	 * In TC hlr_location_cancel_request_update, the GMM_ATTACH_COMPL came 2ms too late, so that the Location Cancel Request
+	 * arrived before it. This results in a test case failure.
+	 * Delay execution by 50 ms
+	 */
+	f_sleep(0.05);
 }
 
 private function f_TC_attach(charstring id) runs on BSSGP_ConnHdlr {