Fix backcompat for hotplug of SCSI controllers
SCSI controllers have no trouble existing without any attached
disks. This could be achieved with the (legacy) monitor syntax
pci_add pci_addr=auto storage if=scsi
This is now denied with
scsi requires a backing file/device.
failed to add if=scsi
There is no need for this denial and it breaks compatability
with existing QEMU usage, so remove the check for presence
of a drive.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>