demo(ionSlideBox): update top bar

Author: ajoslin

demos/directive/slideBox/appIntro/index.html

@@ -33,7 +33,7 @@
       </button>
     </ion-nav-buttons>
 
-    <ion-slide-box on-slide-changed="slideChanged(index)">
+    <ion-slide-box on-slide-changed="slideChanged($index)">
       <ion-slide>
         <h3>Thank you for choosing the Awesome App!</h3>
         <div id="logo">