Since Oslo has introduced the new opt HostAddress opt[1].
This would ensure that an invalid IP does not pass as
a valid hostname and at the same time retains the
rules required to be followed for the validation of
an acceptable hostname.
[1]:https://review.openstack.org/#/c/358045/
Change-Id: I8cb46f6a55cbece5cecce495de76b6ff06459470
4608a9df43