Enum Autoload updates in root master broke cmssw (since Dec 2017)

Since DE 2017, Root change https://github.com/root-project/root/commit/42f889c02436107da57d45192951176892666083#diff-26414a5107cebe06f2a04ceb65518502 in master branch broke CMSSW ROOT master based Integration builds. We get errors like [a] where trackEta is Enum ( https://github.com/cms-sw/cmssw/blob/09c3fce6626f70fd04223e7dacebf0b485f73f54/DataFormats/BTauReco/interface/TaggingVariable.h#L33 ).

In order to keep CMS Ibs alive , for now we revert root change in our builds.

Cheers,

--Shahzad

[a]

DataFormats/BTauReco/interface/IPTagInfo.h:179:24: error: no member named 'trackMomentum' in namespace 'reco::btau'
      vars.insert(btau::trackMomentum, trackMag, true);
                 ~~~~~~^
DataFormats/BTauReco/interface/IPTagInfo.h:180:24: error: no member named 'trackEta' in namespace 'reco::btau'
     vars.insert(btau::trackEta, trackMom.Eta(), true);