Wikimedia Bugzilla is closed!

I've Installed a Farsi wiki on my computer. I changed a user's language in my wiki from Farsi to English then I wasn't able to change. I've got this error while I was trying to access Preferences  




Internal error - {{SITENAME}}

[3c60149c] /wiki/index.php/%D9%88%DB%8C%DA%98%D9%87:%D8%AA%D8%B1%D8%AC%DB%8C%D8%AD%D8%A7%D8%AA Exception from line 127 of /var/www/wiki/includes/Preferences.php: Global default 'persian' is invalid for field date

Backtrace:

#0 /var/www/wiki/includes/Preferences.php(1281): Preferences::getPreferences(User, RequestContext)
#1 /var/www/wiki/includes/specials/SpecialPreferences.php(58): Preferences::getFormObject(User, RequestContext)
#2 /var/www/wiki/includes/specialpage/SpecialPage.php(673): SpecialPreferences->execute(NULL)
#3 /var/www/wiki/includes/SpecialPageFactory.php(488): SpecialPage->run(NULL)
#4 /var/www/wiki/includes/Wiki.php(298): SpecialPageFactory::executePath(Title, RequestContext)
#5 /var/www/wiki/includes/Wiki.php(596): MediaWiki->performRequest()
#6 /var/www/wiki/includes/Wiki.php(460): MediaWiki->main()
#7 /var/www/wiki/index.php(49): MediaWiki->run()
#8 {main}