Don't require folly::Unit in addTaskFinally
Summary:
In
D3241498 addTaskFuture was fixed to work with function returning void. This however changed addTaskFinally API to not allow finally functor which accepts Try<void>.
folly::fibers generally supports Try<void> so there's no reason to force users to use folly::Unit instead of void for addTaskFinally too.
Reviewed By: yfeldblum
Differential Revision:
D3243893
fb-gh-sync-id:
d1df54738157d2019120103956f59b3971ba25ff
fbshipit-source-id:
d1df54738157d2019120103956f59b3971ba25ff