Confluence Mobile Plugin v5.2 breaks when access Spaces with anonymous access.

After update Confluence Mobile Plugin to v5.2, anonymous access are not possible anymore.

Steps to Reproduce

1. Update Confluence Mobile Plugin in UPM to v5.2
2. Granted anonymous access in Global Permission and Test Space
3. Set Site Homepage to Test Space in General Configuration
4. Access to Confluence with iPad safari

Expected Result

Anonymous redirected to the site homepage which granted anonymous access

Actual Result

• In the iDevice, a banner with following message was thrown:

  Oops! Something went wrong. It's probably us, but it might be you. Check your network connection.
  

• Screenshot:

• In the atlassian-confluence.log:

  2013-10-03 01:07:36,807 ERROR [http-8714-5] [common.error.jersey.ThrowableExceptionMapper] toResponse Uncaught exception thrown by REST service
   -- referer: http://192.168.0.108:8714/plugins/servlet/mobile | url: /rest/mobile/1.0/content/524293 | userName: anonymous
  java.lang.NullPointerException
  	at com.atlassian.confluence.mail.notification.persistence.dao.hibernate.HibernateNotificationDao.findNotificationByUserAndPage(HibernateNotificationDao.java:72)
  	at com.atlassian.confluence.mail.notification.DefaultNotificationManager.getNotificationByUserAndPage(DefaultNotificationManager.java:47)
  	at sun.reflect.GeneratedMethodAccessor596.invoke(Unknown Source)
  	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  	at java.lang.reflect.Method.invoke(Method.java:597)
  	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
  	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
  	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)