Output help information unexpectedly

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

root@control:/tiup-cluster# tiup ctl binlog -pd-urls http://172.19.0.101:14379 -show-offline-nodes -cmd pumps -show-offline-nodes
Usage of binlogctl:
  -V	prints version and exit
  -cmd string
    	operator: "generate_meta", "pumps", "drainers", "update-pump", "update-drainer", "pause-pump", "pause-drainer", "offline-pump", "offline-drainer", "encrypt" (default "pumps")
  -data-dir string
    	meta directory path (default "binlog_position")
  -node-id string
    	id of node, use to update some node with operation update-pump, update-drainer, pause-pump, pause-drainer, offline-pump and offline-drainer
  -pd-urls string
    	a comma separated list of PD endpoints (default "http://127.0.0.1:2379")
  -show-offline-nodes
    	include offline nodes when querying pumps/drainers
  -ssl-ca string
    	Path of file that contains list of trusted SSL CAs for connection with cluster components.
  -ssl-cert string
    	Path of file that contains X509 certificate in PEM format for connection with cluster components.
  -ssl-key string
    	Path of file that contains X509 key in PEM format for connection with cluster components.
  -state string
    	set node's state, can set to online, pausing, paused, closing or offline.
  -text string
    	text to be encrypt when using encrypt command
  -time-zone Asia/Shanghai
    	set time zone if you want save time info in savepoint file, for example Asia/Shanghai for CST time, `Local` for local time

copy the binlogctl and run it directly:

root@control:/tiup-cluster# ./binlogctl  -pd-urls http://172.19.0.101:14379 -show-offline-nodes -cmd pumps -show-offline-nodes
[2020/06/28 09:45:39.708 +00:00] [INFO] [nodes.go:53] ["query node"] [type=pump] [node="{NodeID: 172.19.0.103:8250, Addr: 172.19.0.103:8250, State: offline, MaxCommitTS: 417683720428060673, UpdateTime: 2020-06-28 09:35:47 +0000 UTC}"]
[2020/06/28 09:45:39.708 +00:00] [INFO] [nodes.go:53] ["query node"] [type=pump] [node="{NodeID: 172.19.0.104:8250, Addr: 172.19.0.104:8250, State: offline, MaxCommitTS: 417683745355333633, UpdateTime: 2020-06-28 09:37:22 +0000 UTC}"]
[2020/06/28 09:45:39.709 +00:00] [INFO] [nodes.go:53] ["query node"] [type=pump] [node="{NodeID: 172.19.0.105:8250, Addr: 172.19.0.105:8250, State: online, MaxCommitTS: 417683875542335489, UpdateTime: 2020-06-28 09:45:39 +0000 UTC}"]

2. What did you expect to see?
   should normally run as I run binlogctl directly while run it by tiup ctl binlog ...

3. What did you see instead?
   I think the flag is not passed correctly so..

4. What version of TiUP are you using (tiup --version)?
   v1.0.7