gbproxy: Check SGSN-orignated BVC RESET if BSS BVC is gone

IF the BSS-BVC is gone gbproxy blocks the BVC towards the SGSN (this is
the only thing it can do since there is no BVC-REMOVE). If the SGSN ever
decides to reset that BVC the gbproxy should not ACK it, but instead
consider the BVCI unknown.

Change-Id: Ic57b39a77adf71abda99ef8af7da1592e2225a0d
Related: SYS#5628, OS#5236
diff --git a/library/BSSGP_Emulation.ttcnpp b/library/BSSGP_Emulation.ttcnpp
index 593abd8..8d27fd1 100644
--- a/library/BSSGP_Emulation.ttcnpp
+++ b/library/BSSGP_Emulation.ttcnpp
@@ -323,7 +323,9 @@
 
 	/* Messages with BVCI = 0 (Signaling) in BVCI field of NS */
 	[] BSCP.receive(f_BnsUdInd(tr_GLOBAL_SIG, 0)) -> value udi {
-		GLOBAL.send(udi.bssgp);
+		if (GLOBAL.checkstate("Connected")) {
+			GLOBAL.send(udi.bssgp);
+		}
 		}
 	[] BSCP.receive(f_BnsUdInd(tr_RIM, 0)) -> value udi {
 		if (RIM.checkstate("Connected")) {