Promises are used incorrectly about fbjs

[zpao]

Newer versions of fbjs should have that correct (see

fbjs/packages/fbjs/src/core/Deferred.js

Line 25 in 94c3af4

_promise: Promise<any>;

). Probably just need to update fbemitter.

FWIW, there are other, unrelated, issues with fbjs, Promises, and Flow due to our use of a non-standard Promise def. You're already pulling that lib in via your flowconfig so it's not a big deal for you, but just in case you see other problems.

[zpao]

FWIW, I did the upgrade & published [email protected].