Comment 4 for bug 1524169

Reviewed: https://review.openstack.org/256330
Committed: https://git.openstack.org/cgit/openstack/networking-bgpvpn/commit/?id=5b530c24da811957548cf01d28e94dbafd8db558
Submitter: Jenkins
Branch: master

commit 5b530c24da811957548cf01d28e94dbafd8db558
Author: Thomas Morin <email address hidden>
Date: Fri Dec 11 11:35:50 2015 +0100

    Fix RT/RD validation

    This change fixes the RT/RD validation code:
    - use the same validation function for route_targets than
      the one used for import_rts and export_rts
    - allow an empty value without allowing everything
      (_validate_rt_list_or_none was accepting anything non-empty)
    - add unit tests testing the validation of the four RT/RD fields

    Change-Id: I8769b0b135d9c9108475a4366c53266787228beb
    Closes-Bug: 1524169