Use CSUM_BITS instead of incorrect copy.

Sponsored by:	Nginx, Inc.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271005 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Clean up unused CSUM_FRAGMENT.

Sponsored by:	Nginx, Inc.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271006 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Retire thread_unthread(), it has only one caller.  Update comment in
the block of code before the previous call to thread_unthread().

Discussed with:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271007 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Style.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271008 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f