qemu-iotests: add support for vdi format "static" option

VDI supports an image option 'static'.
Ignore "static=off" from qemu-img output.
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

tests/qemu-iotests/common.rc

@@ -61,8 +61,8 @@ _make_test_img()
     	sed -e "s#$IMGFMT#IMGFMT#g" | \
 	sed -e "s# encryption=off##g" | \
 	sed -e "s# cluster_size=0##g" | \
-	sed -e "s# compat6=off##g"
-
+	sed -e "s# compat6=off##g" | \
+	sed -e "s# static=off##g"
 }
 
 _cleanup_test_img()