Simon Marlow authored Apr 01, 2017 and Ben Gamari committed Apr 01, 2017

* If the package flags haven't changed, don't do initPackages (which
  might take multiple seconds in extreme cases)

* Provide a way to change the log_action without invalidating the
  summary cache.

Test Plan: validate

Reviewers: niteria, bgamari, austin, erikd, ezyang

Reviewed By: bgamari

Subscribers: mpickering, rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3392