Node revision access check is broken

The 6.x-3.13 is introducing a bug when checking permission on older revisions.

        elseif (!$denied && $revision_node = node_load($content['nid'], $revision_id) && _node_revision_access($revision_node, 'view')) {
          // You have access to the node as well as that particular revision.
          $revision_access = TRUE;
        }

The middle clause with the value assignment needs to be wrapped in parenthese due to operator precendency.