fix compiler warnings

[smuzaffar]

fixed various compilation warninsg for slc6. Identical fixes are already in 7XX releases

• missing virtual destructors
• explicit type conversions

[cmsbuild]

A new Pull Request was created by @smuzaffar (Malik Shahzad Muzaffar) for CMSSW_5_3_X.

fix compiler warnings

It involves the following packages:

HiggsAnalysis/CombinedLimit

@cmsbuild, @vadler, @nclopezo, @monttj can you please review it and eventually sign? Thanks.
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@smuzaffar you are the release manager for this.
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[smuzaffar]

+tested
Tested at: ab5f621
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-6139/550/summary.html

[vadler]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_5_3_X IBs unless changes (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @smuzaffar, @ktf, @davidlange6, @smuzaffar

[davidlange6]

+1