Removal of Resource.metadata attribute not backwards compatible

[Steve Baker]

Resource.metadata should be restored, but using it should log a deprecation warning

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/96618

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/96618
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=19a8dbfa5ffb6467fd6abeb76afb4c6f7997044e
Submitter: Jenkins
Branch: master

commit 19a8dbfa5ffb6467fd6abeb76afb4c6f7997044e
Author: Steve Baker <email address hidden>
Date: Fri Jun 13 12:49:52 2014 +1200

    Restore resource metadata attribute

    For backwards compatibility the Resource.metadata attribute
    has been restored, however reading or assigning this attribute
    will result in a deprecation warning.

    Reading metadata will force a refresh from the database, which
    maintains the previous behaviour rather than optimising for
    performance.

    Change-Id: Ifdcf3d98b99a09aac8755c84ef3f59d8602fc6a8
    Closes-Bug: #1324704