DragonFly 4.2.1 released

[Justin Sherrill]

Yep, it's a 0.0.1 release, to fix a bug in i915 support.  If you
aren't running an Intel chipset, there's no urgent need to update.
You do not have to be at 4.2.0 to update to 4.2.1; for all intents and
purposes, 4.2.1 can be treated the same as 4.2.0.

I've uploaded the new images and they should be showing up on mirrors shortly.

For those already running DragonFly, the same update methods as before apply:

> cd /usr/src
> git fetch origin
> git branch DragonFly_RELEASE_4_2 origin/DragonFly_RELEASE_4_2
> git checkout DragonFly_RELEASE_4_2
> git pull

And then rebuild:

> make buildworld
> make buildkernel
> make installkernel
> make installworld
> make upgrade

Any existing 4.2 packages you have installed are completely compatible.