Convert deprecated dynamic constructors
Convert deprecated dynamic constructors

Summary: get rid of annoying build warnings.

Reviewed By: spalamarchuk

Differential Revision: D3114718

fb-gh-sync-id: 2e081fccf4b40efd7c1960d18523eecacd562a58
fbshipit-source-id: 2e081fccf4b40efd7c1960d18523eecacd562a58

facebook/mcrouter,yqzhang/mcrouter,yqzhang/mcrouter,yqzhang/mcrouter,yqzhang/mcrouter,facebook/mcrouter,facebook/mcrouter,facebook/mcrouter