Rename 'dbus_object' with 'task'
Rename 'dbus_object' with 'task'

We were exploiting the fact it was a task rather than a plain
dbus object, so this makes the code more obvious.

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

xapi-project/message-switch,xapi-project/message-switch,xapi-project/message-switch