Add a test for permission Acquisition on comments.

We use a different workflow for comments:
The View permission is acquired instead of given explicitly,
as outlined in https://dev.plone.org/ticket/12531.

plone/app/discussion/tests/profile/workflows.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<object name="portal_workflow" meta_type="CMF Workflow Tool">
+ <object name="comment_workflow_acquired_view" meta_type="Workflow"/>
+ <bindings>
+  <type type_id="Discussion Item">
+   <bound-workflow workflow_id="comment_workflow_acquired_view"/>
+  </type>
+ </bindings>
+</object>