shell script mistakes in sandbox

[lpstudy]

I found some minor mistakes of shell scripts in sandbox directory.

1. "$1"x == "master_slave" extra x is missed in master_slave
2. when adopting raft mode, sleep 5 seconds is not enough for the system to run. I encounted bfs_client put error when deploying raft mode by sleep 5-10 seconds.
3. I think it is not good to show process not found when running clear.sh. Killing the process should work without any error message. For the new guy like me to run deploy.sh and get the message process not found, I think there is something wrong with the deploy.sh. However, it works OK.
4. cd - will print current work directory when using start_bfs.sh. I also think this log is unnecessary. It doesn't give any useful information about the system. But the logs like nameserver 0 started ok at port xxx, chunkserver 0 started ok at port xxx should be added into the script, to make it more clear.