Remove "phd.pid-directory" configuration and stop passing "piddir" to daemons

Summary: Ref T13321. The daemons no longer write PID files, so we no longer need to pass any of this stuff to them.

Test Plan: Grepped for affected symbols.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13321

Differential Revision: https://secure.phabricator.com/D20608