include system package state in cache key
include system package state in cache key

Summary: Using system packages changes the binaries, so include the used packages in the cache key when present

Reviewed By: krallin

Differential Revision: D32693534

fbshipit-source-id: c0494667b57040dde680cea3e8e00d77ef48403b

facebook/watchman,facebook/watchman,nodakai/watchman,nodakai/watchman,facebook/watchman,nodakai/watchman,nodakai/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,nodakai/watchman,nodakai/watchman,nodakai/watchman,facebook/watchman,facebook/watchman,facebook/watchman,nodakai/watchman,facebook/watchman