[MERGE] Minor adjustment to tutorial to use single quotes instead of double quotes

[Martin Pool]

Martin Pool has voted +1.
Status is now: Approved
Comment:
Merged to http://sourcefrog.net/bzr/doc

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C20070403231438.822D03AC081%40wander%3E