Fix "daemons running as wrong user" setup issue

Summary:
Fixes T9385. This was accidentally mangled a bit a long time ago by D12797, which was a 1,000-file change which got almost everything right.

Simplify the message and fix all the %s conversions and how they map to parameters.

Test Plan:

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9385

Differential Revision: https://secure.phabricator.com/D15722