Bug 862125 - Properly quote addon id when passing string to querySelector. r=bnicholson

mobile/android/chrome/content/aboutAddons.js

@@ -221,7 +221,7 @@ var Addons = {
 
   _getElementForAddon: function(aKey) {
     let list = document.getElementById("addons-list");
-    let element = list.querySelector("div[addonID='" + aKey + "']");
+    let element = list.querySelector("div[addonID=" + aKey.quote() + "]");
     return element;
   },