Rearrange libbe.ui.command_line.CmdOptionParser._add_option() for Python 2.5

Rearrange libbe.ui.command_line.CmdOptionParser._add_option() for Python 2.5

Python 2.6 doesn't mind, but 2.5 doesn't like kwargs after a *
expansion:

  $ ./be list
  Traceback (most recent call last):
    File "./be", line 5, in <module>
      import libbe.ui.command_line
    File "/home/wking/src/fun/be/be.restructure/libbe/ui/command_line.py", line 63
      *opt_strings, action='callback', dest=dest,
                         ^
  SyntaxError: invalid syntax