Fixes the Javascript interface methods from not working properly when targeting API 17. See http://developer.android.com/reference/android/webkit/WebView.html#addJavascriptInterface(java.lang.Object, java.lang.String). Refs #405.

git-svn-id: https://android.svn.wordpress.org/trunk@887 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0