[TMVA] Simplify GetTree copying of results
[TMVA] Simplify GetTree copying of results

olifre/root,root-mirror/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,karies/root,karies/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,karies/root,karies/root,root-mirror/root,olifre/root,olifre/root,karies/root,karies/root,karies/root,olifre/root,olifre/root,karies/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,root-mirror/root,karies/root