fix a compiler error on es3

GL_MULTISAMPLE is not defined for ES3

Rendering/OpenGL2/vtkOpenGLRenderer.cxx

@@ -630,12 +630,14 @@ void vtkOpenGLRenderer::DevicePickRender()
   this->RenderWindow->MakeCurrent();
   vtkOpenGLClearErrorMacro();
 
+#if GL_ES_VERSION_3_0 != 1
   bool msaaWasEnabled = false;
   if (this->RenderWindow->GetMultiSamples() > 0 && glIsEnabled(GL_MULTISAMPLE))
   {
     glDisable(GL_MULTISAMPLE);
     msaaWasEnabled = true;
   }
+#endif
 
   this->UpdateCamera();
   this->UpdateLightGeometry();
@@ -645,10 +647,13 @@ void vtkOpenGLRenderer::DevicePickRender()
 
   this->PickInfo->PerformedHardwarePick = true;
 
+#if GL_ES_VERSION_3_0 != 1
   if (msaaWasEnabled)
   {
     glEnable(GL_MULTISAMPLE);
   }
+#endif
+
   vtkOpenGLCheckErrorMacro("failed after DevicePickRender");
 }