permission denied problem with old dpdk vhost interfaces after updating ovs to 2.8+

[zenghui.shi]

when updating ovs to 2.8+ in newton, there will be a vhost_socket folder created for dpdkvhostuserclient mode interfaces(at /var/lib/vhost_socket). but for old dpdk instances, vhost_socket interface were created under /var/run/openvswitch folder and remain in that
folder after ovs update. Since the files in /var/run/openvswitch has 0755 mode, qemu cannot access them even it's in the same hugetlbfs group with openvswitch, this in turn causes permission denied errors.

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: stable/ocata
Review: https://review.openstack.org/562148

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: stable/newton
Review: https://review.openstack.org/564423

[OpenStack Infra (hudson-openstack)]

Change abandoned by zenghui.shi (<email address hidden>) on branch: stable/ocata
Review: https://review.openstack.org/562148
Reason: abandon for ocata.
patch for newton: https://review.openstack.org/564423

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/564423
Committed: https://git.openstack.org/cgit/openstack/tripleo-heat-templates/commit/?id=93476eb49fa60ad7373060fb720b39a610794016
Submitter: Zuul
Branch: stable/newton

commit 93476eb49fa60ad7373060fb720b39a610794016
Author: Zenghui Shi <email address hidden>
Date: Thu Apr 26 16:29:43 2018 +0800

    Change ovs RuntimeDirectory Mode

    when updating ovs to 2.8+, ovs and qemu share the
    same group hugetlbfs, but for existing vhostusermode
    interfaces located at /var/run/openvswitch dir, qemu
    can't access them after ovs update, because the dir
    has default 0755 mode instead of a group write
    permission. This change is going to add g+w mode to
    /var/run/openvswitch.

    Change-Id: If9687fee5171d395585d72a923b50903a94297a7
    Related-Bug: #1764971