instance's directory is not removed at destination host during rollback of pre_live_migration

[ChangBo Guo(gcb)]

In method pre_live_migration, we create instance's directory at destination host during block live migration.
If some exceptions happen before creating domain succesfully like failure of connecting volume to destination host,
then we can't destroy instance in method rollback_live_migration_at_destination.
In this case we don't remove the instance's directory, this will lead anDestinationDiskExists when live migratin same instance to same destination.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/134693

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/134693
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=be22375255e471bd187f98972210e79e9b7eafcd
Submitter: Jenkins
Branch: master

commit be22375255e471bd187f98972210e79e9b7eafcd
Author: ChangBo Guo(gcb) <email address hidden>
Date: Fri Nov 14 13:42:41 2014 +0800

    libvirt: clean instance's directory when block migration fails

    In method pre_live_migration, we create instance's directory at destination
    host during block live migration. If some exceptions happen before creating
    domain succesfully like failure of connecting volume to destination host,
    then we can't destroy instance in method rollback_live_migration_at_destination.
    In this case we don't remove the instance's directory, this will lead an
    DestinationDiskExists when live migration same instance to same destination.
    This commit ensure the instance's directory is always cleaned at destination
    host. This commit also extracts instance path calculation into a utility function.

    Closes-Bug: #1392947
    Change-Id: If86e73b07f17d28078ee48983e9e92aafb30d913

[Michal Jura (mjura)]

I've backported this fix to Juno