Update api-ref to include volume_image_metadata

The detailed information for a volume can include "volume_image_metadata"
in the case where the volume was created from an image, or in the case
where the volume was created from a snapshot of such a volume.

Update the API ref to include the field so we accurately represent
the code.

Change-Id: If5fcdefaa10bfb00e60aa4559d3282d3c6a53752
Closes-Bug: #1732763

api-ref/source/v2/parameters.yaml

@@ -1744,6 +1744,14 @@ volume_id_6:
   in: body
   required: false
   type: string
+volume_image_metadata:
+  description: |
+    List of image metadata entries.  Only included for volumes that were
+    created from an image, or from a snapshot of a volume originally created
+    from an image.
+  in: body
+  required: false
+  type: object
 volume_name:
   description: |
     The volume name.

api-ref/source/v2/volumes-v2-volumes.inc

@@ -104,6 +104,7 @@ Response Parameters
    - os-vol-mig-status-attr:migstat: os-vol-mig-status-attr:migstat
    - metadata: metadata
    - status: status_3
+   - volume_image_metadata: volume_image_metadata
    - description: description
    - multiattach: multiattach
    - source_volid: source_volid
@@ -319,6 +320,7 @@ Response Parameters
    - os-vol-mig-status-attr:migstat: os-vol-mig-status-attr:migstat
    - metadata: metadata
    - status: status_3
+   - volume_image_metadata: volume_image_metadata
    - description: description
    - multiattach: multiattach
    - source_volid: source_volid

api-ref/source/v3/parameters.yaml

@@ -2758,6 +2758,14 @@ volume_id_7:
   in: body
   required: true
   type: string
+volume_image_metadata:
+  description: |
+    List of image metadata entries.  Only included for volumes that were
+    created from an image, or from a snapshot of a volume originally created
+    from an image.
+  in: body
+  required: false
+  type: object
 volume_name:
   description: |
     The volume name.

api-ref/source/v3/volumes-v3-volumes.inc

@@ -111,6 +111,7 @@ Response Parameters
    - os-vol-mig-status-attr:migstat: os-vol-mig-status-attr:migstat
    - metadata: metadata
    - status: status_3
+   - volume_image_metadata: volume_image_metadata
    - description: description
    - multiattach: multiattach
    - source_volid: source_volid
@@ -333,6 +334,7 @@ Response Parameters
    - os-vol-mig-status-attr:migstat: os-vol-mig-status-attr:migstat
    - metadata: metadata
    - status: status_3
+   - volume_image_metadata: volume_image_metadata
    - description: description
    - multiattach: multiattach
    - source_volid: source_volid