[PATCH] Convert tws(4) from timeout(9) to callout(9)

[John Baldwin]

This patch converts tws(4) from timeout(9) to callout(9).  It also fixes a few 
places that were tearing down and setting up in the interrupt handler where it 
was not safe to do so and adds some missing teardown actions.  The patch is 
against HEAD but probably applies to 9 and 10 as well.

http://people.freebsd.org/~jhb/patches/tws_callout.patch

-- 
John Baldwin