Changes since CMSSW_10_0_0_pre3:
CMSSW_10_0_0_pre3...CMSSW_10_0_0_pre3_G4VecGeom
CMSDIST Changes between Tags REL/CMSSW_10_0_0_pre3/slc6_amd64_gcc630 and REL/CMSSW_10_0_0_pre3_G4VecGeom/slc6_amd64_gcc630:
- cms-sw/cmsdist#3649 from @cms-sw: Revert "Switch to CLHEP 2.4.0.0"
- cms-sw/cmsdist#3648 from @smuzaffar: merge geant4 changes from root6 branch
- cms-sw/cmsdist#3616 from @civanch: Switch to CLHEP 2.4.0.0