crash if no wifi dongle is plugged in

[hungerpirat]

from the logs:

2015-06-12 10:02:25,698 - netconnectd.server - INFO - Waiting for connection on socket...
2015-06-12 10:02:30,704 - netconnectd.server - INFO - Recv: '{"status":{}}\x00'
2015-06-12 10:02:30,802 - netconnectd.server - ERROR - Got an error while processing message from client, aborting
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/netconnectd-0.1.0_dev_39_g881e76b-py2.7.egg/netconnectd/server.py", line 164, in _socket_monitor
    ret, result = callbacks[message.cmd](message)
  File "/usr/local/lib/python2.7/dist-packages/netconnectd-0.1.0_dev_39_g881e76b-py2.7.egg/netconnectd/server.py", line 426, in on_status_message
    current_ssid, current_address = self.current_wifi
  File "/usr/local/lib/python2.7/dist-packages/netconnectd-0.1.0_dev_39_g881e76b-py2.7.egg/netconnectd/server.py", line 485, in current_wifi
    iwconfig_output = subprocess.check_output(["/sbin/iwconfig", self.wifi_if])
  File "/usr/lib/python2.7/subprocess.py", line 544, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
CalledProcessError: Command '['/sbin/iwconfig', 'wlan0']' returned non-zero exit status 237
2015-06-12 10:02:30,812 - netconnectd.server - INFO - Waiting for connection on socket...

the output of the command itself on the commandline is:

pi@mrbeam ~ $ /sbin/iwconfig wlan0
wlan0     No such device