Update docs to reflect exposure of image 'owner' in v2.

The image 'owner' property was exposed by
https://review.openstack.org/#/c/69887/ .
This updates the docs to show that.

Change-Id: I341acf5384a7c37effc9a6d14073cd4a82307696
Closes-bug: #1277344

api-ref/src/wadls/image-api/src/v2/samples/schemas-image-get-response.json

@@ -103,6 +103,11 @@
             "description": "Operating system version as specified by the distributor",
             "type": "string"
         },
+        "owner": {
+            "description": "Owner of the image",
+            "maxLength": 255,
+            "type": "string"
+        },
         "protected": {
             "description": "If true, image will not be deletable.",
             "type": "boolean"

api-ref/src/wadls/image-api/src/v2/samples/schemas-images-get-response.json

@@ -110,6 +110,11 @@
                         "description": "Operating system version as specified by the distributor",
                         "type": "string"
                     },
+                    "owner": {
+                        "description": "Owner of the image",
+                        "maxLength": 255,
+                        "type": "string"
+                    },
                     "protected": {
                         "description": "If true, image will not be deletable.",
                         "type": "boolean"