Removed DQM and PoolDBOutputServices from threaded jobs

The DQM and PoolDBOutputServices have not been updated to use the new Service APIs
and therefore can not run under the threaded framework. The dropNonMTSafe customize
function now excludes those two Services.
Merge pull request #1948 from Dr15Jones/removeMoreNonUpdatedServices

Multithreading fixes -- Removed DQM and PoolDBOutputServices from threaded jobs
Merge remote branch 'origin/CMSSW_7_0_X' into CMSSW_7_0_X