fix shaderless crash

pandatool/src/mayaegg/mayaToEggConverter.cxx

@@ -1312,7 +1312,7 @@ make_polyset(const MDagPath &dag_path, const MFnMesh &mesh,
         vert.set_normal(LVector3d(n[0], n[1], n[2]));
       }
 
-      if (shader->has_projection()) {
+      if (shader != (MayaShader *)NULL && shader->has_projection()) {
         // If the shader has a projection, use it instead of the
         // polygon's built-in UV's.
         vert.set_uv(shader->project_uv(p3d));

pandatool/src/mayaprogs/mayaPview.cxx

@@ -93,9 +93,12 @@ doIt(const MArgList &) {
   framework.get_models().instance_to(window->get_render());
 
   if (!convert(framework.get_models())) {
+    cerr << "failure in conversion.\n";
     return MS::kFailure;
   }
 
+  cerr << "successfully converted.\n";
+
   loading_np.remove_node();
   window->center_trackball(framework.get_models());
   window->loop_animations();