Migrate to New Random Service Interface

Migrate to the new random number service interface
designed for multithreaded execution.Also remove
a potential memory leak from TxCalculator. Note that
neither of the two classes modified is used or referenced
by anything in CMSSW.
Merge pull request #2436 from wddgit/migrateToNewRandomServiceInterface2

Multithreading fixes -- Migrate to New Random Service Interface