Don't cache ReposUseT constraints
Don't cache ReposUseT constraints

Summary: `ReposUseT` constraints don't need to go into the cache, and it's a waste of time to store them there and do unnecessary lookups.

Reviewed By: samwgoldman

Differential Revision: D17888980

fbshipit-source-id: 4b2707e7914363bc565a76841f6edb5f84ecfc05

nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow