Patches for updated gvinum

Hi,

Gvinum just got better. At least, that's what I hope. Lukas rewrote gvinum to
use a simpler and easier to handle single-thread event system, and I have been
adapting existing code to this. The result can be found in the patches here:

http://folk.ntnu.no/lulf/patches/freebsd/gvinum

One is for current, and the other is for RELENG_6. The code is not tested on
RELENG_6 yet, but I expect I'll do that soon.

This patch includes some missed gvinum features, as well as improvements on old
ones. It is completely compatible with old vinum/gvinum configurations, so there
should not be any problems with upgrading. However, even though it might seem to
work for us, that might not be the case for others! Therefore, I hope many will
test this patch and help discovering bugs that otherwise would just stay there.

I'm also working on a test-suite, so one easily can identify the correctness of
gvinum, but there will probably be cases where my tests are not sufficient.

-- 
Ulf Lilleengen