kernel - general cleanup and mplock removal

* General cleanup and remove use of the mplock in multiple non-critical
  functions.

* Might slightly improve performance if programs run uname(),
  gethostname(), or getdomainname() a lot.
hammer - kqueue filterops are MPSAFE

* Hammer's kqueue filterops are MPSAFE, set appropriate flag.
tmpfs - remove most mp->mnt_token cases, kqueue filterops are MPSAFE

* tmpfs's kqueue filterops are MPSAFE, set appropriate flag.

* tmpfs's vnops frontend universally obtained the tmpfs mnt_token, but
  most of tmpfs's underlying code was already sub-locked by node.

  Remove most mnt_token use cases and make the portions that were not
  safe, safe.  This was primarily the directory lookup and scanning
  code and code to create, delete, and rename files.

* Should greatly improve tmpfs concurrency.
Add missing whitespace in some manual pages.
ipsec - Add missing reference when so_pcb is attached.

* This fixes a panic on disconnection/detaching in the raw socket.
* Fix inspired in rts_attach()

Reported-by: David BERARD
Dragonfly-bug: <http://bugs.dragonflybsd.org/issues/1848>