R1:46bd6b30f8fd

Fix undefined ACTION_BLOCK class constant in Herald

Summary: Fixes T9054. This didn't get fully cleaned up.

Test Plan: Edited several rules, saw actions faithfully represented.

Reviewers: joshuaspence, chad

Reviewed By: chad

Maniphest Tasks: T9054

Differential Revision: https://secure.phabricator.com/D13781