Added 'edit' field to 'getcommitmessage' conduit calls.

Summary:
Server log was showing errors for undefined index 'edit'.

Test Plan:
arc lint

Reviewed By: jungejason
Reviewers: jungejason, grglr
Commenters: grglr
CC: aran, epriestley, grglr, jungejason, tuomaspelkonen
Differential Revision: 217

src/workflow/amend/ArcanistAmendWorkflow.php

@@ -109,6 +109,7 @@ EOTEXT
       'differential.getcommitmessage',
       array(
         'revision_id' => $revision_id,
+        'edit'        => false,
       ));
 
     if ($this->getArgument('show')) {

src/workflow/commit/ArcanistCommitWorkflow.php

@@ -100,6 +100,7 @@ EOTEXT
       'differential.getcommitmessage',
       array(
         'revision_id' => $revision_id,
+        'edit'        => false,
       ));
 
     if ($this->getArgument('show')) {