$DragonFly$ in the docs

[Justin C. Sherrill]

Sascha noticed that when he was committing the txt version of the
handbook, the $DragonFly$ tags floating about in the config chapter caused
some issues.  Anyone think that there be a problem with taking them out? 
The examples where they show don't need them, for the purpose of the
example.

Here's one spot:
http://leaf.dragonflybsd.org/~justin/handbook/configtuning-cron.html
Or 3 times in here:
http://leaf.dragonflybsd.org/~justin/handbook/configtuning-configfiles.html

That should be all occurrences.  If nobody objects, I'll remove them.