Update hsc2hs submodule

Authored by ckoparkar on Sep 13 2018, 5:15 PM.

Description

Update hsc2hs submodule

Test Plan: ./validate

Reviewers: bgamari, hvr, RyanGlScott

Reviewed By: RyanGlScott

Subscribers: monoidal, rwbarton, carter

Differential Revision: https://phabricator.haskell.org/D5114

(cherry picked from commit ce240b3f998b68853c47ab131126eb9a245256c5)