fix(ripple): prevent null error while using ripple

Author: ajoslin

src/core/services/ripple/ripple.js

@@ -154,7 +154,7 @@ function InkRippleService($window, $timeout) {
 
     function updateElement(elem) {
       var index = ripples.indexOf(elem),
-          state = states[index],
+          state = states[index] || {},
           elemIsActive = ripples.length > 1 ? false : isActive,
           elemIsHeld   = ripples.length > 1 ? false : isHeld;
       if (elemIsActive || state.animating || elemIsHeld) {
@@ -188,7 +188,7 @@ function InkRippleService($window, $timeout) {
           css = getRippleCss(size, left, top),
           elem = getRippleElement(css),
           index = ripples.indexOf(elem),
-          state = states[index];
+          state = states[index] || {};
 
       rippleSize = size;