[gh-590] Re-add Workbench patch that was wiped out in 76ffc01a

sites/all/modules/workbench_moderation/workbench_moderation.module

@@ -642,6 +642,10 @@ function workbench_moderation_node_presave($node) {
       $node->status = 0;
     }
   }
+  if (isset($node->workbench_moderation['updating_live_revision']) && !empty($node->book['bid'])) {
+    // Book module forces new revision in book_node_presave() that needs to be cancelled.
+    $node->revision = 0;
+  }
 }
 
 /**