Remove all edge events

Summary:
Ref T5245. These were a bad idea.

We no longer need actors for edge edits either, so remove those. Generally, edges have fit into the policy model as pure/low-level infrastructure, and they do not have any policy or capability information in and of themselves.

Test Plan: `grep`

Reviewers: chad, btrahan, joshuaspence

Reviewed By: joshuaspence

Subscribers: epriestley

Maniphest Tasks: T5245

Differential Revision: https://secure.phabricator.com/D9840

src/applications/diffusion/controller/DiffusionCommitEditController.php

@@ -34,8 +34,8 @@ final class DiffusionCommitEditController extends DiffusionController {
       $new_proj_phids = array_values($proj_phids);
       $rem_proj_phids = array_diff($current_proj_phids,
                                    $new_proj_phids);
-      $editor         = id(new PhabricatorEdgeEditor());
-      $editor->setActor($user);
+
+      $editor = id(new PhabricatorEdgeEditor());
       foreach ($rem_proj_phids as $phid) {
         $editor->removeEdge($commit_phid, $edge_type, $phid);
       }