Comment 2 for bug 1533076

Reviewed: https://review.openstack.org/274976
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=163d46bdc8bbfa2e7da2989f5a5d608826de2dcc
Submitter: Jenkins
Branch: master

commit 163d46bdc8bbfa2e7da2989f5a5d608826de2dcc
Author: huangtianhua <email address hidden>
Date: Wed Jan 13 14:17:57 2016 +0800

    Fix prepare_for_replace/restore_prev_rsrc handing for server

    Now, we set 'fixed_ips' to [] for server ports when prepare
    for server replacement, but the ports are still in-use if only
    set 'fixed_ips' to []. So this patch will to detach the ports from
    nova server to make sure same ports can be attached to new one in
    prepare_for_replace(). Also, when restoring server, we need to detach
    ports from existing server, and then to attach them to previous
    server.

    We check the interface attach/detach complete by list the
    server.interfaces, this change will use 'retry' wrapper to re-poll
    the server interfaces for several times (by new config option
    'max_interface_check_attempts', default is 10), then will raise
    exception if the attach/detach still not complete.

    Closes-Bug: #1533076
    Change-Id: I7b322f9cf16c100dcd0365bc3091c289f00f0548