62XSLHC - fix metUncertaintyTools for scheduled processing

[vadler]

Backport of #3929

[cmsbuild]

A new Pull Request was created by @vadler (Volker Adler) for CMSSW_6_2_X_SLHC.

62XSLHC - fix metUncertaintyTools for scheduled processing

It involves the following packages:

PhysicsTools/PatUtils

@nclopezo, @vadler, @cmsbuild, @Degano, @monttj can you please review it and eventually sign? Thanks.
@TaiSakuma, @nhanvtran this is something you requested to watch as well.
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@andersonjacob, @mark-grimes you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[andersonjacob]

merge

passing tests: 10000,10200,10400,11200,11400,12000,12800,13000,13600,14600
failing tests: 12200 Step2-FAILED code 34304,12400 Step2-FAILED code 34304,12600 Step1-FAILED code 34304,13800 Step2-FAILED code 34304,14000 Step2-FAILED code 34304,14200 Step2-FAILED code 34304,14400 Step2-FAILED code 34304