170. [cleanup] Remove inter server consistancy checks from zone,
these should return as a seperate module in 9.1.
dns_zone_checkservers(), dns_zone_checkparents(),
dns_zone_checkchildren(), dns_zone_checkglue().
Remove dns_zone_setadb(), dns_zone_setresolver(),
dns_zone_setrequestmgr() these should now be found
via the view.