remove_protocol() in bird_cfg_creator.py fails

[andreasbourges]

from_conf is not known to this method:

   def remove_protocol(self, protocol, name):
        if protocol in self.protocols.keys() and name in self.protocols[protocol]:
            if self.protocols[protocol][name][from_conf]:
                raise Exception('cannot delete %s protocol named "%s", it is from conf file' % (protocol, name))

...and causes a runtime-error:

if self.protocols[protocol][name][from_conf]:                                         │
  NameError: name 'from_conf' is not defined

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