Synchronize working copies before doing a "bypassCache" commit read

Summary:
Ref T4292. When the daemons make a query for repository information, we need to make sure the working copy on disk is up to date before we serve the response, since we might not have the inforamtion we need to respond otherwise.

We do this automatically for almost all Diffusion methods, but this particular method is a little unusual and does not get this check for free. Add this check.

Test Plan:

• Made this code throw.
• Ran bin/repository reparse --message ..., saw the code get hit.
• Ran bin/repository lookup-user ..., saw this code get hit.
• Made this code not throw.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4292

Differential Revision: https://secure.phabricator.com/D15783