Add debug trace
Return empty string instead of undef is displayName not set
Merge branch 'master' into scabrero/users-fix-empty-displayname
Removed debug
Fixed the attribute name for displayName when setting or deleting it and fixed the Tree User widget when displayName is undef
Merge pull request #1111 from Zentyal/scabrero/users-fix-empty-displayname

Scabrero/users fix empty displayname