bot.py imports daemonize , which was a custom module in compat.
In core, its use was migrated in December 2008, but the module wasnt included.
https://www.mediawiki.org/wiki/Special:Code/pywikipedia/6136
I incorrectly added package 'daemonize' https://pypi.python.org/pypi/daemonize as a dependency in September 2014 https://gerrit.wikimedia.org/r/#/c/159269/