Verified as follows - No validation error observed in instance XML

# yum list installed | grep openstack-nova
openstack-nova-api.noarch            2015.1.4-30.el7ost      @rhelosp-7.0-puddle
openstack-nova-cert.noarch           2015.1.4-30.el7ost      @rhelosp-7.0-puddle
openstack-nova-common.noarch         2015.1.4-30.el7ost      @rhelosp-7.0-puddle
openstack-nova-compute.noarch        2015.1.4-30.el7ost      @rhelosp-7.0-puddle
openstack-nova-conductor.noarch      2015.1.4-30.el7ost      @rhelosp-7.0-puddle
openstack-nova-console.noarch        2015.1.4-30.el7ost      @rhelosp-7.0-puddle
openstack-nova-novncproxy.noarch     2015.1.4-30.el7ost      @rhelosp-7.0-puddle
openstack-nova-scheduler.noarch      2015.1.4-30.el7ost      @rhelosp-7.0-puddle


# virsh dumpxml 2 |grep tap -A5 -B3
    <interface type='bridge'>
      <mac address='fa:16:3e:c6:3c:7b'/>
      <source bridge='qbrc276cc36-f4'/>
      <target dev='tapc276cc36-f4'/>
      <model type='virtio'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='file'>

# virsh dumpxml 2 > 2.xml
# virt-xml-validate 2.xml
2.xml validates

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHSA-2017-0282.html