Ceph test_discard_bytes unit test takes up too much ram and disk space

[Alex Meade]

The test is using around 512 MB of ram and disk space due to it creating strings of great length and writing them to a file. This is because the test is using the default 128MB chunk size for volumes.

The ramifications of this bug are that you need to run the unit tests on a node with excess of 512MB of free ram and disk.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/154122

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/154122
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=b1c5d16055b3aad6d7ae6bb6df90c645c3897075
Submitter: Jenkins
Branch: master

commit b1c5d16055b3aad6d7ae6bb6df90c645c3897075
Author: Alex Meade <email address hidden>
Date: Mon Feb 2 16:18:15 2015 -0500

    Limit ram and disk used by ceph backup tests

    The test_discard_bytes test in
    cinder/tests/test_backup_ceph.py uses a lot of
    ram and disk space since it tests the ceph driver with
    the default chunk size of 128Mi. This patch lowers it
    to use 1024 bytes instead.

    Closes-bug: #1417293

    Change-Id: I387650bc5ffe57ad8a4cacd1fca5d039fec38eed