Allow a trailing dot in a hostname on diag_dns.php. Fixes #9276
(cherry picked from commit e56c473d7c4c2e7de71c43420c844e452dbcfa82)
Allow a trailing dot in a hostname on diag_dns.php. Fixes #9276
(cherry picked from commit e56c473d7c4c2e7de71c43420c844e452dbcfa82)