Internal directory is disabled after upgrade to Confuence 3.5.x when atlassian-user.xml contains only osuser tag

Internal directory is disabled after upgrade to Confuence 3.5.x, when atlassian-user.xml contains only osuser repository:

<atlassian-user>
    <repositories>
    	<osuser key="osuserRepository" name="OSUser Repository"/>
    </repositories>
</atlassian-user>

The work around is to update the database and enable the directory.

Otherwise, make sure that the hibernate repository is included prior to the upgrade.