Bump mtl, parsec, text submodules (again)

Authored by RyanGlScott on Aug 16 2017, 10:50 AM.

Description

Bump mtl, parsec, text submodules (again)

We failed to add dist-install and dist-boot to .gitignore in the commits
brought in via commit e054c5f06451def4437d9d770ae156f034796c59. This round of
submodule commits should do the trick.