Fix embedded mcrouter mode
Fix embedded mcrouter mode

Summary: ProxyRequestContext requires sendReply to be called.

Test Plan: build it

Reviewed By: @alikhtarov

Differential Revision: D1894816
facebook/mcrouter,glensc/mcrouter,yqzhang/mcrouter,easyfmxu/mcrouter,synecdoche/mcrouter,seem-sky/mcrouter,leitao/mcrouter,nvaller/mcrouter,zhlong73/mcrouter,zhlong73/mcrouter,glensc/mcrouter,yqzhang/mcrouter,seem-sky/mcrouter,synecdoche/mcrouter,tempbottle/mcrouter,evertrue/mcrouter,tempbottle/mcrouter,synecdoche/mcrouter,apinski-cavium/mcrouter,glensc/mcrouter,apinski-cavium/mcrouter,facebook/mcrouter,nvaller/mcrouter,tempbottle/mcrouter,is00hcw/mcrouter,facebook/mcrouter,is00hcw/mcrouter,nvaller/mcrouter,is00hcw/mcrouter,is00hcw/mcrouter,yqzhang/mcrouter,glensc/mcrouter,yqzhang/mcrouter,seem-sky/mcrouter,easyfmxu/mcrouter,evertrue/mcrouter,easyfmxu/mcrouter,leitao/mcrouter,easyfmxu/mcrouter,zhlong73/mcrouter,evertrue/mcrouter,leitao/mcrouter,reddit/mcrouter,apinski-cavium/mcrouter,evertrue/mcrouter,facebook/mcrouter,seem-sky/mcrouter,tempbottle/mcrouter,zhlong73/mcrouter,leitao/mcrouter,synecdoche/mcrouter,apinski-cavium/mcrouter,nvaller/mcrouter,reddit/mcrouter,reddit/mcrouter,reddit/mcrouter