fix to be able to change shebang

There also needs to be changed shebang.

Because, I will not found own package path.

```
$ sudo /etc/init.d/my-agent start
Starting fo-agent:                                         [  OK  ]
$ sudo /etc/init.d/my-agent restart
/etc/init.d/my-agent: /usr/sbin/my-agent: /opt/td-agent/embedded/bin/ruby: bad interpreter: No such file or directory
```