Minor cleanup - use addChild(workspace, true)

TBR=neil.fraser@gmail.com
BUG=104

Review URL: https://codereview.appspot.com/7232051

git-svn-id: http://blockly.googlecode.com/svn/trunk@604 c400ca83-b69d-9dd7-9705-49c6b8615e23
make

git-svn-id: http://blockly.googlecode.com/svn/trunk@605 c400ca83-b69d-9dd7-9705-49c6b8615e23