zhufl eb10e43782 api-ref: add response body for set-image-metadata-for-a-volume
https://developer.openstack.org/api-ref/block-storage/v3/index.html?expanded=set-image-metadata-for-a-volume-detail#set-image-metadata-for-a-volume
"Set image metadata for a volume" interface has response body,
so this is to add response parameter and response example for it.

Change-Id: I8139fd557cb3123dd71ab104e7e36546b862e345
2018-12-10 10:19:17 +08:00
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2018-08-15 08:18:28 -05:00