GlusterFS snapshot code uses new qemu-img arguments

[Eric Harney]

The GlusterFS snapshot code introduced in Havana uses arguments for qemu-img (--backing-chain and --output=json) that are newer than the versions of qemu-img that Cinder is generally expected to support.

Additionally, some code was added to parse qemu-img output rather than using the well-tested image_utils methods which do this today.

This code should not call qemu-img --backing-chain or --output=json, and should leverage image_utils as much as possible for the work being done with qemu_img.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/46761

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/46762

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/46761
Committed: http://github.com/openstack/cinder/commit/bd1a8482c530376acc5fedbaa46477cc003766ce
Submitter: Jenkins
Branch: master

commit bd1a8482c530376acc5fedbaa46477cc003766ce
Author: Eric Harney <email address hidden>
Date: Fri Sep 6 23:26:46 2013 -0400

    Do not use qemu-img --backing-chain or --output=json

    Initial code for GlusterFS snapshot support in Havana
    used qemu-img arguments which are too new to run in many
    environments. Run qemu-img using only arguments which
    will exist on older platforms.

    Partial-Bug: #1224030
    Change-Id: I5155dac492da67a951ede978c2c46a54c239eb04

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/46762
Committed: http://github.com/openstack/cinder/commit/f8ac42460dca22f83a59097530f73b282129cc2b
Submitter: Jenkins
Branch: master

commit f8ac42460dca22f83a59097530f73b282129cc2b
Author: Eric Harney <email address hidden>
Date: Sun Sep 8 10:18:18 2013 -0400

    GlusterFS: Use image_utils for qemu-img calls

    Code added for GlusterFS snapshot support in Havana included
    new code to parse qemu-img output. This removes this code
    and uses image_utils qemu_img_info instead.

    Add test to image_utils for parsing a different style of
    qemu-img info output.

    Improve GlusterFS driver test coverage with tests for cloning,
    create from snapshot, and initialize_connection.

    Closes-Bug: #1224030
    Change-Id: I8f1811b400c06edb3cd7416c52aa297921841e54