Merge branch 'master' of https://github.com/nasa/openmctweb into open33

platform/features/imagery/src/directives/MCTBackgroundImage.js

@@ -64,7 +64,7 @@ define(
 
                     if (!url) {
                         loaded = myCounter;
-                        element.css('background-image', undefined);
+                        element.css('background-image', 'none');
                     } else {
                         image = $document[0].createElement('img');
                         image.src = url;

platform/features/imagery/test/directives/MCTBackgroundImageSpec.js

@@ -92,7 +92,7 @@ define(
 
                 expect(mockElement.css.mostRecentCall.args).toEqual([
                     "background-image",
-                    undefined
+                    "none"
                 ]);
             });
         });