coreos-base/oem-azure: use cloud-init --oem flag

sdk_container/src/third_party/coreos-overlay/coreos-base/oem-azure/files/cloud-config.yml

@@ -2,10 +2,6 @@
 
 coreos:
   units:
-    - name: user-cloudinit@var-lib-waagent-CustomData.path
-      command: start
-      runtime: true
-
     - name: waagent.service
       command: start
       runtime: true
@@ -19,6 +15,17 @@ coreos:
         Type=simple
         ExecStart=/usr/share/oem/python/bin/python /usr/share/oem/bin/waagent -daemon
 
+    - name: oem-cloudinit.service
+      command: restart
+      runtime: yes
+      content: |
+        [Unit]
+        Description=Cloudinit from Azure metadata
+
+        [Service]
+        Type=oneshot
+        ExecStart=/usr/bin/coreos-cloudinit --oem=azure
+
   oem:
     id: azure
     name: Microsoft Azure