Moved context switching in main loop

Problem: The context was set in the main loop just prior to the event
offloading. This yielded the problem that it was not set correctly
during determination of event durations thus picking the duration from
wrong RNGs.

Solution: Moved context switching prior to duration determination.

src/sim/csimulation.cc

@@ -674,6 +674,10 @@ void cSimulation::doOneEvent(cMessage* msg)
             throw cRuntimeError("Activity-Model not supported with Horizon.");
         }
 
+		// set the context for sequential execution
+		setContext(mod);
+		setContextType(CTX_EVENT);
+
 		simtime_t duration = msg->getEventDuration();
 		bool sequentialExecution = (duration == SimTime::simTimeSequentialExecution);
 
@@ -699,10 +703,6 @@ void cSimulation::doOneEvent(cMessage* msg)
 		}
 		else
 		{
-			// set the context for sequential execution
-			setContext(mod);
-			setContextType(CTX_EVENT);
-
 			EVCB.simulationEvent(msg);
 
 			msg->setPreviousEventNumber(event_num);