Unit test extension for context classes

Extend existing unit tests to cover the
content of the context classes as they are
passed to the services in the callback
functions.
Merge branch 'CMSSW_7_0_X' of https://github.com/cms-sw/cmssw into unitTestServiceContexts
Fix new unit test by removing release name from test comparison.
Merge branch 'CMSSW_7_0_X' of https://github.com/cms-sw/cmssw into unitTestServiceContexts
Merge pull request #279 from wddgit/unitTestServiceContexts

Unit test extension for context classes