Don't ask user to use saved message in arc diff --verbatim

Test Plan:
Cancel `arc diff`.
Verify that the message is created.
Run `arc diff --verbatim` and see no reuse message question.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Koolvin

Differential Revision: https://secure.phabricator.com/D2390

src/workflow/diff/ArcanistDiffWorkflow.php

@@ -1290,6 +1290,7 @@ EOTEXT
 
     $template = null;
 
+    if (!$this->getArgument('verbatim')) {
       $saved = $this->readScratchFile('create-message');
       if ($saved) {
         $where = $this->getReadableScratchFilePath('create-message');
@@ -1319,6 +1320,7 @@ EOTEXT
           $this->removeScratchFile('create-message');
         }
       }
+    }
 
     $template_is_default = false;
     $notes = array();