Fixed rare null intent crash on IntentServices

* Setting setIntentRedelivery(true) to always include the last intent if Android kills the IntentService before it finishes.

Author: jkasten2

OneSignalSDK/onesignal/src/main/java/com/onesignal/GcmIntentService.java

@@ -45,6 +45,7 @@ public class GcmIntentService extends IntentService {
 
    public GcmIntentService() {
       super("GcmIntentService");
+      setIntentRedelivery(true);
    }
 
    // Called when GCM message is received from Google or a notification is being restored.

OneSignalSDK/onesignal/src/main/java/com/onesignal/NotificationExtenderService.java

@@ -77,6 +77,7 @@ void override(OverrideSettings overrideSettings) {
 
    public NotificationExtenderService() {
       super("NotificationExtenderService");
+      setIntentRedelivery(true);
    }
 
    private OSNotificationDisplayedResult osNotificationDisplayedResult;