Add metadefs for Cinder volume type configuration

https://review.openstack.org/268357
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commit 44629deb81d153b673d520af44d384b59bfb1a31
Author: Mitsuhiro Tanino <email address hidden>
Date: Fri Jan 15 17:12:35 2016 -0500

    Add metadefs for Cinder volume type configuration

    The following Cinder patch adds support to specify Cinder volume type
    via cinder_img_volume_type parameter in glance properties on image
    metadata. The property should be added in the Metadata Definitions
    catalog.

    https://review.openstack.org/#/c/258649/

    DocImpact: Add cinder_img_volume_type to Image service property
               keys list at CLI reference.
               http://docs.openstack.org/cli-reference/glance.html
    Change-Id: I3bbb20fdf153e12b7461fa9ea9fa172a8d603093
    Depends-On: I62f02d817d84d3a7b651db36d7297299b1af2fe3