Avoid breaking cordova-plugin-local-notifications

Conflicting implementation of didRegisterUserNotificationSettings
prevents cordova-local-notifications-plugin from being notified of success.
emoving it fixes the problem as it was redundant (simply calls
registerForRemoteNotifications, which is called anyway from PushPlugin:init
right after registerUserNotificationSettings).

Fixes phonegap/phonegap-plugin-push/issues/183 and
katzer/cordova-plugin-local-notifications/issues/695