For every vhd 'base image' b, create a file b.readme
For every vhd 'base image' b, create a file b.readme

The file has two purposes:
  1. it records the names of files which reference this one
  2. it describes in english what the file is for, and why
     it shouldn't be carelessly manually deleted

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@eu.citrix.com>

djs55/ffs,franciozzy/ffs,xapi-project/ffs,robertbreker/ffs