crtools: Keep cr_dump_task's post-dump ret code

Broken by 09b7b57c.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -1814,5 +1814,5 @@ err:
 		pr_info("Dumping finished successfully\n");
 	}
 
-	return post_dump_ret ? : ret;
+	return post_dump_ret ? : (ret != 0);
 }

crtools.c

@@ -313,7 +313,7 @@ int main(int argc, char *argv[])
 	if (!strcmp(argv[optind], "dump")) {
 		if (!tree_id)
 			goto opt_pid_missing;
-		return cr_dump_tasks(tree_id) != 0;
+		return cr_dump_tasks(tree_id);
 	}
 
 	if (!strcmp(argv[optind], "pre-dump")) {