Added diffDiskSettings property as part of Swagger changes needed for…

… Ephemeral VM\VMSS

specification/compute/resource-manager/Microsoft.Compute/stable/2018-06-01/compute.json

@@ -5176,6 +5176,31 @@
         "modelAsString": true
       }
     },
+    "DiffDiskOption": {
+      "type": "string",
+      "description": "Specifies the diff disk option for operating system disk. Possible values are: Local.",
+      "enum": [
+        "Local"
+      ],
+      "x-ms-enum": {
+        "name": "DiffDiskOption",
+        "modelAsString": true
+      }
+    },
+    "DiffDiskSettings": {
+      "properties": {
+        "option": {
+          "$ref": "#/definitions/DiffDiskOption",
+          "description": "Specifies the diff disk option for operating system disk. Possible values are: Local"
+        }
+      },
+      "allOf": [
+        {
+          "$ref": "#/definitions/SubResource"
+        }
+      ],
+      "description": "The parameters of a DiffDiskSettings for operating system disk."
+    },
     "ManagedDiskParameters": {
       "properties": {
         "storageAccountType": {
@@ -5228,6 +5253,10 @@
           "type": "boolean",
           "description": "Specifies whether writeAccelerator should be enabled or disabled on the disk."
         },
+        "diffDiskSettings": {
+         "$ref": "#/definitions/DiffDiskSettings",
+          "description": "Specifies the Diff Disk Settings for the operating system disk used by the virtual machine."
+        },
         "createOption": {
           "$ref": "#/definitions/CreateOption",
           "description": "Specifies how the virtual machine should be created.<br><br> Possible values are:<br><br> **Attach** \\u2013 This value is used when you are using a specialized disk to create the virtual machine.<br><br> **FromImage** \\u2013 This value is used when you are using an image to create the virtual machine. If you are using a platform image, you also use the imageReference element described above. If you are using a marketplace image, you  also use the plan element previously described."
@@ -6388,6 +6417,10 @@
           "$ref": "#/definitions/CreateOption",
           "description": "Specifies how the virtual machines in the scale set should be created.<br><br> The only allowed value is: **FromImage** \\u2013 This value is used when you are using an image to create the virtual machine. If you are using a platform image, you also use the imageReference element described above. If you are using a marketplace image, you  also use the plan element previously described."
         },
+        "diffDiskSettings": {
+         "$ref": "#/definitions/DiffDiskSettings",
+          "description": "Specifies the Diff Disk Settings for the operating system disk used by the virtual machine scale set."
+        },
         "diskSizeGB": {
           "type": "integer",
           "format": "int32",