Provides mvd_v20e_tr

As requested https://redmine.cbm.gsi.de/issues/2411 and privately via
email. This geometry is a translation by 40cm of mvd_v20a and is to used
in the coordinate change validation process.

mvd/mvd_v20e_tr.geo.info

+
+MVD version mvd_v20e_tr is a translation of mvd_v20a by 40cm
+which is consistent with a change of coordinate system from the old target position
+to the centre of the magnet. The following cling commands were exceuted.
+
+
+TFile* file = TFile::Open("mvd_v20a_tr.geo.root")
+TFile* newfile = TFile::Open("mvd_v20e_tr.geo.root","RECREATE")
+TGeoVolume* top = (TGeoVolume *) file->Get("Top")
+TGeoNodeMatrix* gnm = (TGeoNodeMatrix *) top->GetNode(0)
+TGeoTranslation* trans = new TGeoTranslation(0,0,-40)
+TGeoMatrix* mat = trans
+gnm->SetMatrix(mat)
+newfile->WriteTObject(top)
+newfile->Close()
+file->Close()
+