Only request storage permission on JB and older.

The permission to read local, application external directory is granted
implicitly in KitKat and later versions.

app/src/main/AndroidManifest.xml

@@ -3,9 +3,8 @@
       android:installLocation="auto" xmlns:android="http://schemas.android.com/apk/res/android">
     <uses-permission android:name="android.permission.INTERNET"/>
     <uses-permission android:name="android.permission.VIBRATE"/>
-    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
-    <!-- Allow writing to external storage -->
-    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" android:maxSdkVersion="18" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18" />
 
   <!-- OpenGL ES 2.0 -->
   <uses-feature android:glEsVersion="0x00020000" />