Debug Stream recovery, addition of HLT_rejected_events histogram

Introduce an additional histogram to HIST_DEBUGSTREAMON.ntup.root that contains the number of HLT rejected events.

Changes to dbgAnalysis.py: addition of a function that adds the extra histogram to the root file after the Pre tree has been filled. Changes to trigRecoExe.py: in post execute, count the number of rejected events in log.BSRDOtoRAW in the existing loop that merges the child log files and call on the function to create histograms before the Pos tree is filled.

@wiedenma @mark

ATR-26595

HLT/Trigger/TrigTransforms/TrigTransform/python/dbgAnalysis.py

@@ -279,5 +279,4 @@ def getHltDecision(rejected, outputFile):
     # Close output TFile
     hfile.Write("HLT_rejected_events",TFile.kOverwrite)
     hfile.Close()
-
-
+    return msg.info("Added HLT_rejeceted_events to %s", outputFile)