[cleanup] Remove "panoramio" and "special_page_limit" settings in config2.py
[cleanup] Remove "panoramio" and "special_page_limit" settings in config2.py

With I570d822dc a deprecation warning is printed if a deprecated variable
is set inside user-config.py but not exists in config2.py

Change-Id: Ic0025b602d01837172ef80fc32772cd9b847d6c7

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