TRestMetadata::InstantiateChildMetadata resets metadata after loading parameters

[AlvaroEzq]

TRestMetadata::InstantiateChildMetadata calls the metadata Initialize() method after loading its members from the config element. Thus, the child metadata members are reset. I think the call to Initialize() should be before the LoadConfigFromElement() call.

framework/source/framework/core/src/TRestMetadata.cxx

Lines 801 to 802 in df3eb05

	md->LoadConfigFromElement(paraele, Global, {});
	md->Initialize();

This was added in commit 5d8cb71 but I dont know what was the reason for it.

I found this when trying to debug the TRestCut applied in TRestDataSetPlot, where the cuts are loaded using this TRestMetadata::InstantiateChildMetadata

framework/source/framework/core/src/TRestDataSetPlot.cxx

Line 324 in df3eb05

cut->AddCut((TRestCut*)InstantiateChildMetadata("TRestCut", cutName));

It also appears for loading the TRestCut in TRestDataSet

framework/source/framework/core/src/TRestDataSet.cxx

Line 768 in df3eb05

fCut = (TRestCut*)InstantiateChildMetadata("TRestCut");

and was recently added in TRestDataSetGainMap

framework/source/framework/analysis/src/TRestDataSetGainMap.cxx

Line 189 in df3eb05

fCut = (TRestCut*)InstantiateChildMetadata("TRestCut");

They still work as expected because the TRestCut::Initialize() method

framework/source/framework/core/src/TRestCut.cxx

Line 69 in df3eb05

void TRestCut::Initialize() { fCuts.clear(); }

only clears the fCuts member and not the fCutStrings and fParamCuts, which are the ones used in TRestDataSet::MakeCut(TRestCut*)