message: disable adding histograms to directory also for root merging
diff: #include "TList.h"
  #include "TClass.h"
  #include "AliAnalysisDataContainer.h"
  +#include "TH1.h"
  +#include "TDirectory.h"
  using namespace std;
  @@ -74,6 +76,12 @@ int AliHLTRootObjectMergerComponent::DoInit( int argc, const char** argv )
  {
  ConfigureFromArgumentString(argc, argv);
  + if (getenv("HLT_ONLINE_MODE") && strcmp(getenv("HLT_ONLINE_MODE"), "on") == 0)
  + {
  + TDirectory::AddDirectory(kFALSE);
  + TH1::AddDirectory(kFALSE);
  + }
  +
  HLTInfo("AliHLTRootObjectMergerComponent::DoInit (with QueueDepth %d)", fQueueDepth);
  if (fAsyncProcessor.Initialize(fQueueDepth, fAsyncProcess, fAsyncProcess ? 100000000 : 0)) return(1);
  