Comment 6 for bug 1557003

Reviewed: https://review.openstack.org/298466
Committed: https://git.openstack.org/cgit/openstack/searchlight/commit/?id=531447d28045e0da15a85bf942ee03d7707b3679
Submitter: Jenkins
Branch: stable/mitaka

commit 531447d28045e0da15a85bf942ee03d7707b3679
Author: Rick Aulino <email address hidden>
Date: Tue Mar 15 12:01:54 2016 -0600

    Zero Downtime Re-indexing Error Handling.

    See spec:
    http://specs.openstack.org/openstack/searchlight-specs/specs/mitaka/zero-downtime-reindexing.html

    The Zero Downtime code is deficient in the error handling department.
    One cleanup method too few. If we get any unrecoverable exceptions
    while creating/preparing the indexes or aliases, we cannot continue.
    In this case we need to roll back and undo any changes we made.

    Change-Id: I5591d5208f75015f93b8431e73d2d7c7f5f2e167
    Closes-Bug: #1557003
    (cherry picked from commit bc9eeaa9bac867eb28c07077fe7ee4cc4af9db5f)