Not able to show info window in openvswitch setup

[BernhardGruen]

The info window does not open in a openvswitch cluster:
This is the stack trace:
Traceback (most recent call last):
File "main.py", line 74, in row_clicked
info = infowindow.InfoWindow(instance_name)
File "/home/bjmg/git/ganetiadmin/infowindow.py", line 55, in init
self.input_ip.set_text(','.join(info['nic.bridges']))
TypeError: sequence item 0: expected str instance, NoneType found