Don't show the delete button on a deleted document

Summary:
This doesn't actually contain any logic to prevent a user from deleting a
document twice, but it makes it significantly harder to do so.

Test Plan:
Went to edit a document, saw the delete button. Clicked it, then went back to
the edit view, and no longer saw the delete button.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3952

Author: Ricky Elrod

src/applications/phriction/controller/PhrictionEditController.php

@@ -154,20 +154,22 @@ public function processRequest() {
         ->setErrors($errors);
     }
 
+    $delete_button = null;
     if ($document->getID()) {
       $panel_header = 'Edit Phriction Document';
       $submit_button = 'Save Changes';
-      $delete_button = phutil_render_tag(
-        'a',
-        array(
-          'href' => '/phriction/delete/'.$document->getID().'/',
-          'class' => 'grey button',
-        ),
-        'Delete Document');
+      if ($document->getStatus() != PhrictionDocumentStatus::STATUS_DELETED) {
+        $delete_button = phutil_render_tag(
+          'a',
+          array(
+            'href' => '/phriction/delete/'.$document->getID().'/',
+            'class' => 'grey button',
+          ),
+          'Delete Document');
+      }
     } else {
       $panel_header = 'Create New Phriction Document';
       $submit_button = 'Create Document';
-      $delete_button = null;
     }
 
     $uri = $document->getSlug();