Bump version to 19:0
Bump version to 19:0

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