R1:0d070c91dc8d

Fix Aphlict logging

Summary:
Yeahhhhhhhh....

- Open a "stream", not a "steam".
- Make error easier for users to understand.
- Write to the log in debug mode so the issue is more apparent.

Test Plan:
- Started server with bad permissions, got usable error message.
- Started server with good permissions, got logfile.

Reviewers: joshuaspence, btrahan

Reviewed By: btrahan

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11339