kernel - Remove kernel-level ccms module (it will be moved into hammer2)

kernel - Remove kernel-level ccms module (it will be moved into hammer2)

* Remove the CCMS kernel layer.  The CCMS module is going to be moved
  directly into hammer2 in order to make hammer2 more portable.  For
  now that means moving the files into vfs/hammer2 in the hammer2 branch.

* CCMS is a logical cache coherency locking layer that has been in the
  DragonFly tree for a while but was not enabled by default.  Originally
  the plan was to not lock vnodes across operations but to instead acquire
  the appropriate CCMS lock(s), but rewiring all the filesystems proved to
  be too large a task.

* HAMMER2's cluster work is going to need this layer for real, but nothing
  else does.  What we will do instead (eventually) is add a mount flag to
  allow us to avoid locking vnodes across VNOPS calls which HAMMER2 will be
  able to specify.