BUG: rc not defined

[CJ-Wright]

I get the following doing conda_forge

activity-error:conda_forge:activity failed with execption:
Traceback (most recent call last):
  File "/home/christopher/dev/rever/rever/activity.xsh", line 59, in __call__
    self.func(*args, **kwargs)
  File "/home/christopher/dev/rever/rever/activities/conda_forge.xsh", line 126, in _func
    gh, username = github.login(return_username=True)
  File "/home/christopher/dev/rever/rever/github.xsh", line 106, in login
    write_credfile(credfile)
  File "/home/christopher/dev/rever/rever/github.xsh", line 29, in dec
    return f(*args, **kwargs)
  File "/home/christopher/dev/rever/rever/github.xsh", line 600, in write_credfile
NameError: name 'rc' is not defined

I think this is the problematic line: https://github.com/regro/rever/blob/master/rever/github.xsh#L88