Fuel backup doesn't flush the docker images after completion

[Fabrizio Soppelsa]

`dockerctl backup` doens't remove the temporary docker images after zipping them in the backup file.
When regular backups are performed, this may lead to hundreds of images in /var resulting in a /var fillup.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/170933

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/170933
Committed: https://git.openstack.org/cgit/stackforge/fuel-library/commit/?id=c58cf534df27d7f19515fc9b6d48d3a1edc7a041
Submitter: Jenkins
Branch: master

commit c58cf534df27d7f19515fc9b6d48d3a1edc7a041
Author: Matthew Mosesohn <email address hidden>
Date: Mon Apr 6 20:25:14 2015 +0300

    Clean up temporary images during dockerctl backup

    Images created for backup should be cleaned up to
    conserve disk space on Fuel Master and reduce
    the size of future backups.

    Change-Id: I4adf06219bc1edfd97e7cb8ce350d1da47fd9ba3
    Closes-Bug: #1437245

[Serhii Ovsianikov (sovsianikov)]

Need fix to fuel 6.0

The customer created a large amount of backups of Fuel 6.0 with the “docker backup” utility. There was a large amount of docker images.

The part of the customer's log:

# docker images
fuel/cobbler_6.0_2015-05-11_0501 latest b704f13e6f24 7 days ago 1.099 GB
fuel/mcollective_6.0_2015-05-11_0501 latest f696fc2eb602 7 days ago 272.9 MB
fuel/postgres_6.0 latest 95474357dcc2 8 days ago 347.1 MB
fuel/rabbitmq_6.0 latest 74531b54ff46 8 days ago 370 MB
fuel/keystone_6.0 latest c7f8737f7bbb 8 days ago 333 MB
...
fuel/cobbler_6.0_2015-02-25_1421 latest 773d68adda91 11 weeks ago 1.097 GB
fuel/mcollective_6.0_2015-02-25_1421 latest 63831becbd34 11 weeks ago 271.5 MB
fuel/postgres_6.0_2015-02-25_1342 latest 2ef1721fb48d 11 weeks ago 338 MB
fuel/rabbitmq_6.0_2015-02-25_1342 latest b83ec5feb978 11 weeks ago 372.8 MB
fuel/keystone_6.0_2015-02-25_1342 latest 1502943aef15 11 weeks ago 333.1 MB

Please create the patch in 6.0 as soon as possible

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/6.0
Review: https://review.openstack.org/186853

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/186853
Committed: https://git.openstack.org/cgit/stackforge/fuel-library/commit/?id=a53e527750bebaa8fe13d4978c2ab65f5ec46c02
Submitter: Jenkins
Branch: stable/6.0

commit a53e527750bebaa8fe13d4978c2ab65f5ec46c02
Author: Matthew Mosesohn <email address hidden>
Date: Mon Apr 6 20:25:14 2015 +0300

    Clean up temporary images during dockerctl backup

    Images created for backup should be cleaned up to
    conserve disk space on Fuel Master and reduce
    the size of future backups.

    Change-Id: I4adf06219bc1edfd97e7cb8ce350d1da47fd9ba3
    Closes-Bug: #1437245
    (cherry picked from commit c58cf534df27d7f19515fc9b6d48d3a1edc7a041)