Description of problem:
I get traceback when system is not registered to spacewalk and dnf-plugin-spacewalk is enabled.


Version-Release number of selected component (if applicable):
rhn-client-tools-2.4.8-1.fc22.noarch

How reproducible:
always

Steps to Reproduce:
1. install new system and dnf-plugin-spacewalk
2. without registration to spacewalk or remove row serverURL in /etc/sysconfig/rhn/up2date


Actual results:
[root@test01-64 ~]# dnf update -y
Traceback (most recent call last):
  File "/usr/bin/dnf", line 36, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 198, in user_main
    errcode = main(args)   
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 84, in main
    return _main(base, args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 117, in _main
    cli.configure(map(ucd, args))
  File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 1034, in configure
    self.base.plugins.run_config()
  File "/usr/lib/python2.7/site-packages/dnf/plugin.py", line 82, in fn
    dnf.util.mapall(operator.methodcaller(method), self.plugins)
  File "/usr/lib/python2.7/site-packages/dnf/util.py", line 157, in mapall
    return list(map(fn, *seq))
  File "/usr/lib/python2.7/site-packages/dnf-plugins/spacewalk.py", line 82, in config
    self.activate_channels(self.cli.demands.sack_activation)
  File "/usr/lib/python2.7/site-packages/dnf-plugins/spacewalk.py", line 101, in activate_channels
    login_info = up2date_client.up2dateAuth.getLoginInfo(timeout=self.conf.timeout)
  File "/usr/share/rhn/up2date_client/up2dateAuth.py", line 227, in getLoginInfo
    login(timeout=timeout) 
  File "/usr/share/rhn/up2date_client/up2dateAuth.py", line 194, in login
    li = server.up2date.login(systemId)
  File "/usr/share/rhn/up2date_client/rhnserver.py", line 63, in __call__
    return rpcServer.doCall(method, *args, **kwargs)
  File "/usr/share/rhn/up2date_client/rpcServer.py", line 212, in doCall
    if len(e.args) > 1:
UnboundLocalError: local variable 'e' referenced before assignment