MFC 228207:

MFC 228207:
When changing the user priority of a thread, change the real priority
in addition to the user priority for threads whose current real priority
is equal to the previous user priority or if the new priority is a
real-time priority.  This allows priority changes of other threads to
have an immediate effect.

git-svn-id: svn://svn.freebsd.org/base/stable/9@229619 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f