Remove check for existance of file because it  is not appropriate for unit-test -- the existance of non-empty file is checked at the parsing of cmsShow arguments.
Add test for parse errors.
Merge pull request #1944 from alja/7x_unitttest-confusion

Fireworks fixes -- 70x improve unittest for fireworks configuration.
Merge remote branch 'origin/CMSSW_7_0_X' into CMSSW_7_0_X