Cleanup stale stats
Cleanup stale stats

Summary: those stats are not used anywhere

Test Plan: run mcrouter and see stats are not reported to *.stats file

Reviewed By: alikhtarov@fb.com

Subscribers: alikhtarov

FB internal diff: D1533090

Tasks: 4774100

reddit/mcrouter,apinski-cavium/mcrouter,is00hcw/mcrouter,glensc/mcrouter,easyfmxu/mcrouter,nvaller/mcrouter,is00hcw/mcrouter,evertrue/mcrouter,reddit/mcrouter,reddit/mcrouter,seem-sky/mcrouter,tempbottle/mcrouter,nvaller/mcrouter,is00hcw/mcrouter,easyfmxu/mcrouter,yqzhang/mcrouter,glensc/mcrouter,leitao/mcrouter,easyfmxu/mcrouter,apinski-cavium/mcrouter,yqzhang/mcrouter,is00hcw/mcrouter,glensc/mcrouter,leitao/mcrouter,facebook/mcrouter,nvaller/mcrouter,leitao/mcrouter,apinski-cavium/mcrouter,nvaller/mcrouter,evertrue/mcrouter,evertrue/mcrouter,facebook/mcrouter,leitao/mcrouter,synecdoche/mcrouter,zhlong73/mcrouter,evertrue/mcrouter,yqzhang/mcrouter,seem-sky/mcrouter,easyfmxu/mcrouter,zhlong73/mcrouter,synecdoche/mcrouter,apinski-cavium/mcrouter,zhlong73/mcrouter,reddit/mcrouter,facebook/mcrouter,seem-sky/mcrouter,facebook/mcrouter,tempbottle/mcrouter,seem-sky/mcrouter,glensc/mcrouter,zhlong73/mcrouter,tempbottle/mcrouter,yqzhang/mcrouter,tempbottle/mcrouter,synecdoche/mcrouter,synecdoche/mcrouter