Comment 8 for bug 1239893

It looks to me like ppa.py is a missing a strip() somewhere as DialogAdd.py adds in a "\n".

From DialogAdd.py:

  def check_line(self, *args):
    """
    Check for a valid apt line and set the sensitiveness of the
    button 'add' accordingly
    """
    line = self.entry.get_text() + "\n"