Synnefo

To reproduce:

root@worker1:~# snf-manage server-list --filter-by="userid=vkoukis@grnet.gr" 
Traceback (most recent call last):
  File "/usr/bin/snf-manage", line 9, in <module>
    load_entry_point('snf-webproject==0.13rc6', 'console_scripts', 'snf-manage')()
  File "/usr/lib/python2.6/dist-packages/synnefo/webproject/manage.py", line 344, in main
    mu.execute()
  File "/usr/lib/python2.6/dist-packages/synnefo/webproject/manage.py", line 274, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/pymodules/python2.6/django/core/management/base.py", line 191, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/lib/pymodules/python2.6/django/core/management/base.py", line 220, in execute
    output = self.handle(*args, **options)
  File "/usr/lib/python2.6/dist-packages/synnefo/api/management/commands/server-list.py", line 145, in handle
    pprint_table(self.stdout, table, headers, separator)
  File "/usr/lib/python2.6/dist-packages/synnefo/management/common.py", line 232, in pprint_table
    widths = [max(map(len, col)) for col in zip(*table)]
TypeError: object of type 'NoneType' has no len()