spapr/htab: fix savevm

Commit 3a384297 ("spapr: Add a "no HPT" encoding to HTAB migration stream")
allows to migrate an empty HPT, but doesn't mark correctly the
end of the migration stream.

The end condition (value returned by htab_save_iterate())
should be 1, whereas in 3a384297 it returns 0.

The problem can be reproduced with QEMU monitor command "savevm":
the command never stops and the disk image grows without limit.

Fixes: 3a384297Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

hw/ppc/spapr.c

@@ -1827,7 +1827,7 @@ static int htab_save_iterate(QEMUFile *f, void *opaque)
     /* Iteration header */
     if (!spapr->htab_shift) {
         qemu_put_be32(f, -1);
-        return 0;
+        return 1;
     } else {
         qemu_put_be32(f, 0);
     }