More leaks fixed in MomentumScaleCalibration

As reported by https://cmssdt.cern.ch/SDT/jenkins-artifacts/ib-static-analysis/CMSSW_7_0_X_2013-11-23-0200/slc5_amd64_gcc481/llvm-analysis/report-SE8Wpo.html#EndPath.

@vadler I will by-pass. Shout if not ok.