[ROOT6] Revert change for dd4hep ROOT master until fixed

[mrodozov]

please test
for some reason in ROOT6 and ROOT620 branches DD4 cmake picks system python3 instead of the python2 given by the recipe

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/4835/console Started: 2020/02/24 13:03

[cmsbuild]

A new Pull Request was created by @mrodozov (Mircho Rodozov) for branch IB/CMSSW_11_1_X/rootmaster.

@cmsbuild, @smuzaffar, @mrodozov, @tulamor can you please review it and eventually sign? Thanks.
cms-bot commands are listed here

[mrodozov]

merging this to restart the IBs , dd4 bulilds fine with the old dd4 version

[cmsbuild]

-1

Tested at: efab0c8

CMSSW: CMSSW_11_1_ROOT6_X_2020-02-21-2300
SCRAM_ARCH: slc7_amd64_gcc820
You can see the results of the tests here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-8ab6ad/4835/summary.html

I found follow errors while testing this PR

Failed tests: UnitTests

• Unit Tests:

I found errors in the following unit tests:

---> test testDD4hepFilteredView had ERRORS
---> test DetectorDescriptionDDCMSTestDriver had ERRORS

[cmsbuild]

Comparison job queued.

[mrodozov]

right, this commit didn't worked as well :/