another 2 station mvd

mvd_v20i has station 0 and 1 in their normal placement.
Station 2 and 3, along with the heat sinks have been pushed to outside
normal area of the experiment.

setup/setup_sis18_electron.C

@@ -11,7 +11,7 @@ void setup_sis18_electron()
   // -----  Geometry Tags  --------------------------------------------------
   TString magnetGeoTag    = "v21a";
   TString pipeGeoTag      = "v22d";
-  TString mvdGeoTag       = "v20g_tr";
+  TString mvdGeoTag       = "v20i_tr";
   TString stsGeoTag       = "v21e_sis18";
   TString tofGeoTag       = "v21b_1h_sis18";