Fix kevent's childs priority greediness

Fix kevent's childs priority greediness.  Such tasks were always scheduled
at nice level -5 and, at that time, udev stole us the CPU time with -5.

Already posted at http://lkml.org/lkml/2005/1/10/85



[akpm@linux-foundation.org: add comment]
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>