Migrate out events may happen on tasks that are not in the
runqueue, for example this is the case for tasks that are
sleeping. In this case, we don't want to log the migrate out
event in the source runqueue because the task is not eventually
in the runqueue and we have already logged its sleep event.

This fixes timeslices that spuriously propagate a sleep event
from the previous timeslice.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nikhil Rao <ncrao@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>