gbproxy: Wait longer for BVC unblocking at start-up

When using NS_Provider_FR, the FR links need some more seconds to come
up than the NS_Provider_IP.

Change-Id: Idf80cf6119b67393fe5cbc0c93f5715daddcae0a
diff --git a/gbproxy/GBProxy_Tests.ttcn b/gbproxy/GBProxy_Tests.ttcn
index 242b7e9..e690f34 100644
--- a/gbproxy/GBProxy_Tests.ttcn
+++ b/gbproxy/GBProxy_Tests.ttcn
@@ -367,7 +367,7 @@
 	}
 
 	/* wait until all BVC are unblocked on both sides */
-	timer T := 5.0;
+	timer T := 15.0;
 	T.start;
 	alt {
 	[] SGSN_MGMT.receive(BssgpStatusIndication:{*, ?, BVC_S_UNBLOCKED}) -> value bsi {