Ticket 47337 - mep_pre_op: Unable to fetch origin entry
    
    Bug Description:  After installing IPA, and adding a hostgroup, an error will be written
                      to the error log if you delete this host group(Unable to fetch origin entry).
                      This is caused by the referential integrity plugin trying to cleanup
                      the deleted entry's membership.  This causes the mep plugin to process the
                      delete operation, but it can not find the origin entry(because it is deleted).
    
    Fix Description:  If the operation is internal(from a server plugin) do not write the error
                      to the standard log level.
    
    https://fedorahosted.org/389/ticket/47337
    
    Reviewed by: richm(Thanks!)