scsi: more fixes to properties for passthrough devices

Commit 0384783 (scsi-block: remove properties that are not relevant for
passthrough, 2012-07-09) removed one property that should have been
left there, "bootindex".

It also did not touch scsi-generic, while it should have.

Fix both problems.

Reported-by: Alexandre DERUMIER <aderumier@odiso.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 409f760..21b862d 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -2421,6 +2421,7 @@
 #ifdef __linux__
 static Property scsi_block_properties[] = {
     DEFINE_PROP_DRIVE("drive", SCSIDiskState, qdev.conf.bs),
+    DEFINE_PROP_INT32("bootindex", SCSIDiskState, qdev.conf.bootindex, -1),
     DEFINE_PROP_END_OF_LIST(),
 };