Do not issue the 'task should be finished by now' message if the clock is stopped
This patch prevents the org-clock-sound notification and the
"Task'BLAH' should be finished by now."
message when the termination time is reached and the clock is not
running.
Before this patch spurious notifications and messages were generated when
clocking in a task with estimated effort time remaining. After clocking
out the task the remaining minutes would tick by and then the sound
and message that the task should be finished were generated - even though
you are not working on it anymore.