TrigEgammaHypo: Avoid EventContext TLS lookups.

Don't fetch EventContext from thread-local storage if we already have
it as an argument.

Trigger/TrigHypothesis/TrigEgammaHypo/src/TrigL2CaloHypoAlgMT.cxx

 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
 */
 
 #include "GaudiKernel/Property.h"
@@ -82,7 +82,7 @@ StatusCode TrigL2CaloHypoAlgMT::execute( const EventContext& context ) const {
     }
     d->setObjectLink( "roi", roiELInfo.link );
     
-    TrigCompositeUtils::linkToPrevious( d, previousDecision );
+    TrigCompositeUtils::linkToPrevious( d, previousDecision, context );
     ATH_MSG_DEBUG( "Added view, roi, cluster, previous decision to new decision " << counter << " for view " << (*viewELInfo.link)->name()  );
     counter++;