dump: fix return code in message on pre-dump failure

Obviously we should print pre_dump_ret value if pre-dump failed.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -1499,7 +1499,7 @@ int cr_dump_tasks(pid_t pid)
 
 	pre_dump_ret = run_scripts(ACT_PRE_DUMP);
 	if (pre_dump_ret != 0) {
-		pr_err("Pre dump script failed with %d!\n", post_dump_ret);
+		pr_err("Pre dump script failed with %d!\n", pre_dump_ret);
 		goto err;
 	}
 	if (init_stats(DUMP_STATS))