Comment 6 for bug 1396932

Reviewed: https://review.openstack.org/139063
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=d39349cf47dfe9ac3f52089402d69cd1be8b013b
Submitter: Jenkins
Branch: stable/icehouse

commit d39349cf47dfe9ac3f52089402d69cd1be8b013b
Author: Kevin Benton <email address hidden>
Date: Thu Nov 27 01:45:29 2014 -0800

    Fix hostname validation for nameservers

    Fixes the hostname validation to align with the RFC's demands[1].
    This was done by replacing the full regex with a function that
    broke the FQDN into individual components that were easier to
    reason about with regular expressions.

    Also added several test cases for domains so if someone wants
    to convert it back to pure regex there will be better test vectors.

    1. RFC 1123 says an all-digit hostname is allowed in section 2.1. It
       says that this more liberal syntax MUST be supported.

    Conflicts:
     neutron/tests/unit/test_attributes.py

    Closes-Bug: #1396932
    Change-Id: I003cf14d95070707e43e40d55da62e11a28dfa4e
    (cherry picked from commit 35662d07628452d14306f5197871ad64f6396ff3)