discover/device-handler: Cancel pending boot on reinit
When a reinit is requested device_handler_cancel_default() is
called, however as the name suggests this only cancels the boot task if
it is the result of a default boot option. We also want to cancel a boot
task if it was executed manually because it may have outstanding
asynchronous transfers running, so explicitly cancel it during reinit.
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>