qemu_tree.check_guests_proc_scsi() only compares scsi infos
for qtree/guest, so when there's an ide/virtio_blk device,
call this function is useless.

And it can't distigush a scsi device and a usb device, so
this function call for scsi/usb is also meaningless.
Signed-off-by: NAihua Liang <aliang@redhat.com>