Declare onRequestPermissionResult instead of onRequestPermissionsResult

As noted in the comment, the former is deprecated in favour of the
latter, but the latter is never called. See also:

- apache/cordova-android#1388
- apache/cordova-android#1393

I hope the comment will help us fix the problem quickly when the Cordova
folks decide to remove the deprecated method. (And hopefully make sure
that the new method is called.)

Addresses: https://trello.com/c/zsmadleg/2549-mind-ease-notifications-probably-broken-on-android

src/android/Permission.java

@@ -76,8 +76,12 @@ private void ensure(String name, CallbackContext callbackContext) {
         }
     }
 
+    // This is deprecated in favour of onRequestPermissionsResult, but as of
+    // this writing, Cordova never calls onRequestPermissionsResult. So we have
+    // to use the deprecated method until they fix this.
+    @SuppressWarnings("deprecation")
     @Override
-    public void onRequestPermissionsResult(
+    public void onRequestPermissionResult(
         int requestCode, String[] permissions, int[] grantResults
     ) throws JSONException {
         Log.i(TAG, "Permission request callback called. requestCode: " + requestCode);