Summary: Ref T9252. This mostly cleans up future and log handling, and edges us closer to being able to do useful work with Harbormaster / Drydock.
Test Plan:
- Added a "Run `ls -alh`" step to my trivial build plan.
- Ran it a bunch of times.
- Worked great.
- Also did an HTTP plan.
{F835227}
{F835228}
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T9252
Differential Revision: https://secure.phabricator.com/D14161
