Update scheduler.py
Update scheduler.py

make SCHEDULER_QUEUE_CLASS works!
Lyle-Wong/scrapy,zzz686970/scrapy-redis,lining0806/scrapy-redis,wangjun/scrapy-redis,zhoulunhao/scrapy-redis,ChenglongChen/scrapy-redis,fydlzr/scrapy-redis,younghz/sr-chn,newle/scrapy-redis,rolando/scrapy-redis,Wingszero/scrapy-redis,zhangxf0924/scrapy-redis,srznew/scrapy-redis,linpan/scrapy-redis,raven47git/scrapy-redis,ruitian/scrapy-redis,didoteebin/scrapy-redis,zjc0516/scrapy-redis,songshuang00/scrapy-redis,miminus/scrapy-redis,newle/scrapy-redis,roycehaynes/scrapy-redis,cursesun/scrapy-redis,darkrho/scrapy-redis,younghz/scrapy-redis