mwan3: revert: also cleanup lock on mwan3 stop

This reverts commit cde2a77ed3.

Applying this change has shown that it is even quicker to provoke the
race condtition on simultan mwan3 commands execution.
By reversing the change we have the same behaviour as before.

But the race condition on mwan3 execute at the same time still exists.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
(cherry picked from commit b5bd6d757b)

net/mwan3/files/lib/mwan3/mwan3.sh

@@ -204,13 +204,6 @@ mwan3_unlock() {
 }
 
 mwan3_lock_clean() {
-	for pid in $(pgrep -f "lock /var/run/mwan3.lock"); do
-		kill -TERM "$pid" > /dev/null 2>&1
-	done
-	sleep 1
-	for pid in $(pgrep -f "lock /var/run/mwan3.lock"); do
-		kill -KILL "$pid" > /dev/null 2>&1
-	done
 	rm -rf /var/run/mwan3.lock
 }