ref(user-data): switch get_image to use /deis/platform/version

Author: Gabriel Monroy

contrib/coreos/user-data

@@ -72,7 +72,7 @@ write_files:
 
       # if no image was set in etcd, we use the default plus the release string
       if [ $? -ne 0 ]; then
-        RELEASE=`etcdctl get /deis/release 2>/dev/null`
+        RELEASE=`etcdctl get /deis/platform/version 2>/dev/null`
 
         # if no release was set in etcd, use the default provisioned with the server
         if [ $? -ne 0 ]; then