Set busy indicator to false in refresh callbacks

src/views/app.html

@@ -790,7 +790,7 @@
             <label class="control-label">Task Error</label>
             <p>If a configuration, update, restore or backup action resulted in an error, you can retry the task.</p>
             <p ng-show="app.error">An error occurred during the <b>{{ app.error.installationState | taskName }}</b> operation: <span class="text-danger"><b>{{ app.error.reason + ': ' + app.error.message }}</b></span></p>
-            <button class="btn btn-primary pull-right" ng-click="repair.confirm()" ng-disabled="app.taskId">Retry {{ app.error.installationState | taskName }}</button>
+            <button class="btn btn-primary pull-right" ng-click="repair.confirm()" ng-disabled="app.taskId || !app.error">Retry {{ app.error.installationState | taskName }}</button>
 
             <!-- this is hidden for now, use the CLI instead -->
             <button class="btn btn-danger pull-right" ng-click="repair.stopAppTask(app.taskId)" ng-show="false && app.taskId">Cancel Current Task</button>