The COW object used within VariableHistory can't be serialised itself,
but we can convert it to a dict when serializing and then back when
deserialising. This finally allows DataSmart objects to be serialized.
NOTE: "serialisation" here means pickling, not over XMLRPC or any other
transport.
(Bitbake rev: bbbb2a53d5decf3b613a92c4ff77c84bfc5d4903)
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>