Remove `VerboseLevel:' parameter from TMVA weights files

`VerboseLevel:' parameter is not supported by newer version of ROOT5
and ROOT6. It blocks ROOT6 RelVals from running.

Initially reported in OfflineComputingPlanningMeeting2013121.

Once this is merged IBs fail due to `__CINT__`, `__REFLEX__`, `__MAKECINT__`, and `__ROOTCLING__` macro hell and GCCXML hacks (e.g., `std::shared_ptr` hack).

Once solved above, ROOT6 RelVals fails with:
```
Data member  "m_Parameters" type "double" does not match with the expected type in the mapping "double[6]". from ObjectStreamerBase::buildDataMembers
```

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>