Avoid loading geometry from mesh file twice

Ng_LoadMesh() tries to read the geometry from the mesh file. If it was
read before by Mesh::Load(), the preloaded geometry is replaced by
ng_geometry (which might be garbage)

This is a mere workaround, not a clean solution (Mesh::Load() should
handle everything, including MPI distribution of geometry)

libsrc/meshing/meshclass.cpp

@@ -1660,10 +1660,6 @@ namespace netgen
 	clusters -> Update();
       }
 
-    auto geo = geometryregister.LoadFromMeshFile (infile);
-    if(geo)
-       geometry = geo;
-
     SetNextMajorTimeStamp();
     //  PrintMemInfo (cout);
   }