Remove ancient Remarkup constants from Phame and Maniphest

Summary: Ref T13661. These constants are no longer used.

Test Plan:
For a blog with a nonempty description, viewed the "Manage" page and the home page; saw properly rendered description.

Grepped for removed constants, no hits.

Maniphest Tasks: T13661

Differential Revision: https://secure.phabricator.com/D21749

src/applications/maniphest/storage/ManiphestTask.php

@@ -24,8 +24,6 @@ final class ManiphestTask extends ManiphestDAO
     PhabricatorPolicyCodexInterface,
     PhabricatorUnlockableInterface {
 
-  const MARKUP_FIELD_DESCRIPTION = 'markup:desc';
-
   protected $authorPHID;
   protected $ownerPHID;
 

src/applications/phame/controller/blog/PhameBlogManageController.php

@@ -143,11 +143,6 @@ final class PhameBlogManageController extends PhameBlogController {
         ),
         $feed_uri));
 
-    $engine = id(new PhabricatorMarkupEngine())
-      ->setViewer($viewer)
-      ->addObject($blog, PhameBlog::MARKUP_FIELD_DESCRIPTION)
-      ->process();
-
     $description = $blog->getDescription();
     if (strlen($description)) {
       $description = new PHUIRemarkupView($viewer, $description);

src/applications/phame/storage/PhameBlog.php

@@ -13,8 +13,6 @@ final class PhameBlog extends PhameDAO
     PhabricatorFulltextInterface,
     PhabricatorFerretInterface {
 
-  const MARKUP_FIELD_DESCRIPTION = 'markup:description';
-
   protected $name;
   protected $subtitle;
   protected $description;