Workaround for multithreading.

- Revert back to `edm::EDAnalyzer` JetAnalyzer and METAnalyzer since
  they are calling thread unsafe methods of the DQM, which is not
  allowed for DQMEDAnalyzer derived classes.
Merge pull request #3009 from ktf/fix-dqm-mt

DQM -- Workaround for multithreading.
Merge remote branch 'origin/CMSSW_7_1_X' into CMSSW_7_0_X