Use PhutilConsole in the ./scripts/daemon/exec/exec_daemon.php script

Summary: Use PhutilConsole instead of fwrite.

Test Plan: Is there any reason we can't use PhutilConsole?

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9971