libxl_create: Re-order callbacks of initiate_domain_create

libxl_create: Re-order callbacks of initiate_domain_create

Callbacks should be in the order that there are going to be executed.
This patch fixes the initiate_domain_create callbacks, and also
reorders the callbacks prototypes. That way, it's easier to follow the
flow.

This patch:
- move libxl__colo_restore_setup_done after domcreate_bootloader_done.
- move domcreate_attach_devices after domcreate_devmodel_started.

No functional change.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>