Fix bad "editPolicy" key in Paste

Summary: Fixes T12508. Files don't have an `editPolicy`, and we started actually checking that the keys are real things in D17616.

Test Plan:
  - Before patch: created a paste, got an "editPolicy" exception.
  - After patch: created a paste that worked properly.

Reviewers: avivey, chad

Reviewed By: avivey

Maniphest Tasks: T12508

Differential Revision: https://secure.phabricator.com/D17628

src/applications/paste/xaction/PhabricatorPasteContentTransaction.php

@@ -79,7 +79,6 @@ final class PhabricatorPasteContentTransaction
         'mime-type' => 'text/plain; charset=utf-8',
         'authorPHID' => $actor->getPHID(),
         'viewPolicy' => PhabricatorPolicies::POLICY_NOONE,
-        'editPolicy' => PhabricatorPolicies::POLICY_NOONE,
       ));
   }