Follow change in samba4 beta4 for sid_check_is_domain to sid_check_is_our_sam
With c43505b621725c9a754f0ee98318d451b093f2ed in samba git master
the function sid_check_is_domain() was renamed to sid_check_is_our_sam().
https://fedorahosted.org/freeipa/ticket/2929