Use glance.openstack.common.jsonutils to deal with JSON in test files

[Yanis Guenane]

A great number of test files still uses json.loads() instead of using the wrapper provided by glance.openstack.common.jsonutils

All tests that use json directly should make the switch to the corresponding wrapper in glance.common.openstack.jsonutils

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/60718

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/60718
Committed: https://git.openstack.org/cgit/openstack/glance/commit/?id=16c3a33c0b8c37ea76d45a90d6b332cfda416b3d
Submitter: Jenkins
Branch: master

commit 16c3a33c0b8c37ea76d45a90d6b332cfda416b3d
Author: Yanis Guenane <email address hidden>
Date: Sun Dec 8 22:50:17 2013 +0000

    Migrate json to glance.openstack.common.jsonutils

    Every call to json.loads/json.dumps have been changed to
    jsonutils.loads/jsonutils.dumps respectively. Import json has been removed
    also replaced by import glance.openstack.common.jsonutils

    654d80b416dc5f413cb791aa838ec8688bf7da44 Create openstack.common.jsonutils

    Change-Id: I8ef580e5eb91526dfaef37050ce1f5c6d88d56b5
    Closes-bug: #1257922