Revert AccessUri description to make it correspond to server response (#3433)

Author: lenala

specification/compute/resource-manager/Microsoft.Compute/stable/2018-04-01/disk.json

@@ -1038,6 +1038,26 @@
       "description": "Data used for requesting a SAS."
     },
     "AccessUri": {
+      "properties": {
+        "properties": {
+          "x-ms-client-flatten": true,
+          "$ref": "#/definitions/AccessUriOutput",
+          "description": "Operation output data (raw JSON)"
+        }
+      },
+      "description": "A disk access SAS uri."
+    },
+    "AccessUriOutput": {
+      "properties": {
+        "output": {
+          "x-ms-client-flatten": true,
+          "$ref": "#/definitions/AccessUriRaw",
+          "description": "Operation output data (raw JSON)"
+        }
+      },
+      "description": "Azure properties, including output."
+    },
+    "AccessUriRaw": {
       "properties": {
         "accessSAS": {
           "readOnly": true,