Remove Python 2 check from MutableChainTest
Remove Python 2 check from MutableChainTest

pablohoffman/scrapy,scrapy/scrapy,elacuesta/scrapy,dangra/scrapy,scrapy/scrapy,eLRuLL/scrapy,pawelmhm/scrapy,pablohoffman/scrapy,eLRuLL/scrapy,elacuesta/scrapy,scrapy/scrapy,pablohoffman/scrapy,dangra/scrapy,pawelmhm/scrapy,starrify/scrapy,pawelmhm/scrapy,eLRuLL/scrapy,dangra/scrapy,starrify/scrapy,elacuesta/scrapy,starrify/scrapy