Move shared image error handler to client.js

src/views/apps.html

@@ -31,15 +31,6 @@
   </div>
 </div>
 
-<script>
-    function imageErrorHandler(elem) {
-        'use strict';
-
-        elem.src = elem.getAttribute('fallback-icon');
-        elem.onerror = null;    // avoid retry after default icon cannot be loaded
-    }
-</script>
-
 <div class="content content-large">
 
     <!-- Workaround for select-all issue, see commit message -->