MFC 234927:

MFC 234927:
- Don't log messages saying that accounting is being disabled and enabled
  if the accounting log file is atomically replaced with a new file
  (such as during log rotation).
- Simplify accounting log rotation a bit.  There is no need to re-run
  accton(8) after renaming the new log file to it's real name.

PR:		kern/167321

git-svn-id: svn://svn.freebsd.org/base/stable/8@247322 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f