Fix mount examples in the README

The enabled flag is mandatory.
diff --git a/README.rst b/README.rst
index 67b17c9..8b156cb 100644
--- a/README.rst
+++ b/README.rst
@@ -558,6 +558,7 @@
         enabled: true
         mount:
           samba1:
+          - enabled: true
           - path: /media/myuser/public/
           - device: //192.168.0.1/storage
           - file_system: cifs
@@ -599,6 +600,7 @@
         storage:
           mount:
             data:
+              enabled: true
               device: /dev/vg1/data
               file_system: ext4
               path: /mnt/data