pre-dump: handle errors from page_xfer_dump_pages()

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -1645,6 +1645,10 @@ err:
 		ret = page_xfer_dump_pages(&xfer, ctl->mem_pp, 0);
 
 		xfer.close(&xfer);
+
+		if (ret)
+			break;
+
 		timing_stop(TIME_MEMWRITE);
 
 		destroy_page_pipe(ctl->mem_pp);