[cleanup] config2.py: Remove unused variable _thislevel
[cleanup] config2.py: Remove unused variable _thislevel

Change-Id: Ibb4b15a24c9f0ceadab92c4f23c2ce46ad2f22c6

wikimedia/pywikibot-core,PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core