make conpherence reply handler work

Summary: it doesn't work right now. updating this regex should fix it methinks

Test Plan: gotta push it live

Reviewers: chad, epriestley

Reviewed By: chad

CC: aran, Korvin

Maniphest Tasks: T2399

Differential Revision: https://secure.phabricator.com/D4663

src/applications/metamta/storage/PhabricatorMetaMTAReceivedMail.php

@@ -93,7 +93,7 @@ final class PhabricatorMetaMTAReceivedMail extends PhabricatorMetaMTADAO {
     $prefixPattern = ($single_handle_prefix)
       ? preg_quote($single_handle_prefix, '/') . '\+'
       : '';
-    $pattern = "/^{$prefixPattern}((?:D|T|C)\d+)\+([\w]+)\+([a-f0-9]{16})@/U";
+    $pattern = "/^{$prefixPattern}((?:D|T|C|E)\d+)\+([\w]+)\+([a-f0-9]{16})@/U";
 
     $phabricator_address = null;
     $receiver_name       = null;