fix gl3d plot show-no-WebGL message

- by making sure it scene creation returns early
  when WebGL context creation fails.

Author: etpinard

src/lib/show_no_webgl_msg.js

@@ -31,7 +31,8 @@ module.exports = function showWebGlMsg(scene) {
     };
 
     var div = document.createElement('div');
-    div.textContent = 'Webgl is not supported by your browser - visit https://get.webgl.org for more info';
+    div.className = 'no-webgl';
+    div.textContent = 'WebGL is not supported by your browser - visit https://get.webgl.org for more info';
     div.style.cursor = 'pointer';
     div.style.fontSize = '24px';
     div.style.color = Color.defaults[0];

src/plots/gl3d/scene.js

@@ -204,7 +204,7 @@ function initializeGLPlot(scene, fullLayout, canvas, gl) {
         * The destroy method - which will remove the container from the DOM
         * is overridden with a function that removes the container only.
         */
-        showNoWebGlMsg(scene);
+        return showNoWebGlMsg(scene);
     }
 
     var relayoutCallback = function(scene) {