vhost-user-scsi: add missing virtqueue_size param

vhost-user-scsi: add missing virtqueue_size param

Commit 5c0919d0 [1] introduced virtqueue_size parameter
for common virtio-scsi path, without updaing the vhost-user-scsi
code. vhost-user-scsi devices right now report size 0 for each vq.

This patch introduces virtqueue_size param to vhost-user-scsi,
that can now be set by the user. However, the most importantly, it
now has a default value of 128 (same as QEMU's virtio-scsi).

[1] 5c0919d0 ("virtio-scsi: Add virtqueue_size parameter
allowing virtqueue size to be set.")

Change-Id: I70e87eab702ebf1196c028dbf17d54fdc0c89a14
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Message-Id: <1510676916-76409-1-git-send-email-dariuszx.stojaczyk@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>