deps: upgrade libuv to 1.9.1

Fixes: https://github.com/nodejs/node/issues/4002
Fixes: https://github.com/nodejs/node/issues/5384
Fixes: https://github.com/nodejs/node/issues/6563
Refs: https://github.com/nodejs/node/issues/2680#issuecomment-213521708
PR-URL: https://github.com/nodejs/node/pull/6796


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Myles Borins <myles.borins@gmail.com>