Remove ocaml-libvhd dependency from xapi
Remove ocaml-libvhd dependency from xapi

Partial workaround for [xapi-project/libvhd#4]

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

djs55/planex,djs55/planex,simonjbeaumont/planex,djs55/planex,simonjbeaumont/planex,simonjbeaumont/planex