Updating submodules
Summary:
GitHub commits:
https://github.com/facebook/fb303/commit/
50af07af9a1b6374b44faeb50ed948f56cd33455
https://github.com/facebook/fbthrift/commit/
206bba8e29b52c4f5cacc4638e403b34ce07472d
https://github.com/facebook/watchman/commit/
170ea0e5d165f60fbc28fb23411959d910416f8c
https://github.com/facebookincubator/katran/commit/
2ee002a8087ce0a79f0e07f5359ff01b6fe83fed
https://github.com/facebookincubator/velox/commit/
dffb9b9ce42d4bc18b98d6032fed4ee83b7e0bb2
Reviewed By: jailby
fbshipit-source-id:
7a5f70a68ffbb53e4e567d0f305d58aed2a6867a