Unaccessible variable self.attrs in Tracker
    
    In tracker, 'self.attrs' variable is created and filled in track_create method.
    Some objects are not created but still require access to this variable.
    Created 'self.attrs' variable in init
    
    https://fedorahosted.org/freeipa/ticket/6125
    
    Reviewed-By: Milan Kubik <mkubik@redhat.com>