Update git submodules

Update git submodules

* Update os-brick from branch 'master'
  to d3f4f3b45e201587de21d4431fc4f12f4a5df95a
  - iSCSI: wait for multipathd to remove paths

    While disconnecting the volume, we flush the multipath device,
    execute ``multipath del path`` and remove the individual
    devices before finishing the operation.
    There is an issue with the said order as removing individual
    devices already triggers the uevent for multipathd to remove
    the paths but it doesn't happen immediately.
    With change[1], we tried to mitigate the issue by executing
    ``multipath del path`` manually but this also generates
    another uevent for multipathd and doesn't guarantee that the
    devices are removed synchronously from multipathd monitoring.
    Overall, we are just increasing the number of uevents and
    not guaranteeing that the paths are removed before we
    return the call to caller (nova or cinder or glance).

    This patch addresses the issue by waiting for the paths to
    be removed from multipathd monitoring by introducing a
    call to ``multipathd show paths raw format "%d" `` with an
    exponential backoff. This ensures that the paths are not
    monitored anymore before os-brick claims the removal of
    devices and returns the call.
    As a last mechanism, if the devices are still monitored
    by multipathd, we execute the ``multipath del path``
    command manually to make sure we tried our best to
    remove the devices from multipathd monitoring.

    [1] https://review.opendev.org/c/openstack/os-brick/+/785818

    Closes-Bug: #2136842

    Change-Id: Ie08f9bcbaf31390c33f74d95dde2798e9287a582
    Signed-off-by: Rajat Dhasmana <rajatdhasmana@gmail.com>