NS_Emulation: expect altstep timeout entry only if timer is running

Should fix the following log message:
NS_Emulation.ttcnpp:784 Timeout operation on timer Tns_alive failed: The timer is not started.

Change-Id: If1fae965659f73fde2508b0e9158099025fa65f2
diff --git a/library/NS_Emulation.ttcnpp b/library/NS_Emulation.ttcnpp
index d1700f8..0ed022a 100644
--- a/library/NS_Emulation.ttcnpp
+++ b/library/NS_Emulation.ttcnpp
@@ -781,13 +781,13 @@
 		}
 
 		/* transition to DEAD if t_alive times out */
-		[] Tns_alive.timeout {
+		[Tns_alive.running] Tns_alive.timeout {
 			log("Tns-alive expired: changing to DEAD_BLOCKED + starting Tns-test");
 			f_change_state(NSVC_S_DEAD_BLOCKED);
 			Tns_test.start;
 		}
 
-		[] Tns_test.timeout {
+		[Tns_test.running] Tns_test.timeout {
 			log("Tns-test expired: sending NS-ALIVE");
 			f_sendAlive();
 		}