BSSGP_Emulation: dont fail when removing a non-exitent client

On multiple BSSGP tests the IMSI might not anymore registered to the first BSSGP

Change-Id: Ibad8971e5acc2691da29cf7fa394d1d58eea79a4
diff --git a/library/BSSGP_Emulation.ttcn b/library/BSSGP_Emulation.ttcn
index ea242d3..fa33f51 100644
--- a/library/BSSGP_Emulation.ttcn
+++ b/library/BSSGP_Emulation.ttcn
@@ -321,8 +321,8 @@
 			return;
 		}
 	}
-	setverdict(fail, "Could not find client for IMSI ", imsi);
-	mtc.stop;
+	log("Warning: Could not find client for IMSI ", imsi);
+	return;
 }
 
 /* TS 44.064 7.2.1.1 LLGMM-ASSIGN */