Entity type of NULL in authorization OG

We encountered an issue in our site when (re-)importing users from AD via the feeds module and an LDAP query (this is all working perfectly)

php: Error: Class name must be a valid object or a string in entity_get_controller()

I found that an entity_load on NULL was being executed in the LdapAuthorizationConsumerOG class, populateConsumersFromConsumerIds method. For now we can't figure out where this NULL entity is coming from but I added a simple check to pass any non-existing entities: see the attached patch.

I hope this at least helps someone having similar issues, or perhaps commit it to core LDAP (after review etc) so this edge-case is caught.