usb-redir: Never return USB_RET_NAK for async handled packets

usb-redir: Never return USB_RET_NAK for async handled packets

USB_RET_NAK is not a valid response for async handled packets (and will
trigger an assert as such).

Also drop the warning when receiving a status of cancelled for packets not
cancelled by qemu itself, this can happen when a device gets unredirected
by the usbredir-host while transfers are pending.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit 181133404f520fab40a3ad40d935d91cf3cf546c)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>