Migrate HLTTauDQMOfflineSource to DQMEDAnalyzer
Remove calls to TH1::Sumw2()

They're were probably not needed anyway.
Take HLT menu parsing out of bookHistograms()
Merge pull request #3063 from makortel/tautriggerdqmDQMEDAnalyzer

DQM -- Migrate Tau HLT DQM to DQMEDAnalyzer