Comment 2 for bug 1745572

Reviewed: https://review.openstack.org/530357
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=892c1ec6900c7834964dd912cadab5d7ee3d4f62
Submitter: Zuul
Branch: master

commit 892c1ec6900c7834964dd912cadab5d7ee3d4f62
Author: Bo Chi <email address hidden>
Date: Thu Dec 28 21:35:31 2017 +0800

    fix same mechanism driver called twice bug

    when a mechinism driver calls context.continue_binding to
    continue binding, it will be called again because
    _check_driver_to_bind compares driver name with driver.

    Closes-Bug: #1745572
    Change-Id: I62b32c9b9d01dd929fe8cd3634c78dc0cbe325b6