Bugfix. Removes overlaps

Fixes magnet_v21b position.

Update trd tag in DEC21 lmvm setup.

magnet/magnet_v21b.geo.info

+manget_v20b is shifted by 40 cm consistent with change of coordinate system.
+
+Commands issued.
+
+TFile* file
+TFile* newfile
+file = TFile::Open("magnet_v20b.geo.root")
+TGeoVolume* Top = (TGeoVolume *) file->Get("geometryFromGDML")
+Top->Clone()
+TGeoVolume* newtop = (TGeoVolume *) Top->Clone()
+TGeoNodeMatrix *nm = (TGeoNodeMatrix *) newtop->GetNode(0)
+nm->SetName("magnet_v20b_1")
+nm->GetVolume()->SetName("magnet_v20b")
+newfile = TFile::Open("magnet_v21b.geo.root","CREATE")
+nm->SetMatrix(new TGeoTranslation(0,0,-40))
+newfile->WriteTObject(newtop)
+newfile->Close()
+

setup/setup_sis100_muon_lmvm_DEC21.C

@@ -44,7 +44,7 @@ void setup_sis100_muon_lmvm_DEC21()
   TString pipeGeoTag      = "v21d";
   TString stsGeoTag       = "v21e";
   TString muchGeoTag      = "v21c_sis100_1m_lmvm";
-  TString trdGeoTag       = "v20b_1m";
+  TString trdGeoTag       = "v20c_1m";
   TString tofGeoTag       = "v21a_1m";
   TString platGeoTag      = "v13a";
   // ------------------------------------------------------------------------