unhandled exception when starting lnst-slave if another instance is running

[jtluka]

./lnst-slave -d &
./lnst-slave -d

Traceback (most recent call last):
  File "/home/lnst/lnst/lnst/Slave/NetTestSlave.py", line 733, in __init__
    self._s_socket.bind(addr)
OSError: [Errno 98] Address already in use

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./lnst-slave", line 102, in <module>
    main()
  File "./lnst-slave", line 94, in main
    nettestslave = NetTestSlave(log_ctl, slave_config)
  File "/home/lnst/lnst/lnst/Slave/NetTestSlave.py", line 934, in __init__
    self._server_handler = ServerHandler(("", port), slave_config)
  File "/home/lnst/lnst/lnst/Slave/NetTestSlave.py", line 736, in __init__
    logging.error(e[1])
TypeError: 'OSError' object is not subscriptable