Fix an issue where excluded recipients are not respected
Summary: I broke this in D3778. We modify $parameters and then ignore it in favor of $params for the rest of the method. Unit tests work great since they're one level below this.
Test Plan: Verified "Send email about my own actions" behaved correctly.
Reviewers: vrana, btrahan
Reviewed By: vrana
CC: aran
Differential Revision: https://secure.phabricator.com/D3796