TBRec: Fix compilation warnings.

Compilation warnings: uninitialized variables.

TestBeam/TBRec/src/TBBeamQualityEMFractionTool.cxx

@@ -199,7 +199,7 @@ StatusCode TBBeamQualityEMFractionTool::accept(std::vector<std::string> m_partic
   }  
   
   //Accesing the CaloCellContainer
-  const CaloCellContainer* cellContainer;
+  const CaloCellContainer* cellContainer = nullptr;
   
   sc = m_StoreGate->retrieve(cellContainer);
   if (sc.isFailure()) {

TestBeam/TBRec/src/TBTrackToCaloAlg.cxx

@@ -461,7 +461,7 @@ void TBTrackToCaloAlg::CompareImpactWithCluster()
 
   // loop on clusters
   
-  const CaloClusterContainer* cluster_container;
+  const CaloClusterContainer* cluster_container = nullptr;
   sc1=evtStore()->retrieve(cluster_container,m_cluster_container);
   
   const ImpactInCaloCollection* impact_collection;

TestBeam/TBRec/src/TBXCryYTableRead.cxx

@@ -52,7 +52,7 @@ StatusCode TBXCryYTableRead::execute()
 
   StatusCode sc;
   // Retrieve Event Info from file
-  const TBEventInfo* theEventInfo;
+  const TBEventInfo* theEventInfo = nullptr;
   sc = evtStore()->retrieve(theEventInfo,"TBEventInfo");
   if ( sc.isFailure() ) {
     ATH_MSG_ERROR