Fixes #333.
I cannot reproduce this crash, but looks like the crash happens during
exit, I am thinking perhaps the buddylist window gets closed before the
plugin tries to remove the statusboxes.
/*
* A completely stupid plugin, inspired by a dumb conversation in #gaim
* and needing some light relief from 'real' work.
* Also as a tribute to our fearless project leader.
*
* Copyright (C) 2005-2008 Peter Lawler <bleeter from users.sf.net>