message: tools: don't kill my system running the tests
  With the previous command killing python, this made my whole desktop
  disappear, that's not very nice.
diff: @@ -24,12 +24,10 @@ killall $QUIET gzserver
  killall $QUIET px4
  -pkill -9 -f screen
  -pkill -9 -f python
  -pkill -9 -f run_in_terminal
  -pkill -9 -f mavproxy.py
  -pkill -9 -f ardurover
  -pkill -9 -f arducopter
  +killall $QUIET sim_vehicle.py
  +killall $QUIET mavproxy.py
  +killall $QUIET ardurover
  +killall $QUIET arducopter
  sleep 3
  @@ -37,11 +35,9 @@ killall $QUIET -SIGKILL gzviewer
  killall $QUIET -SIGKILL gzserver
  killall $QUIET -SIGKILL px4
  -pkill -9 -f screen
  -pkill -9 -f python
  -pkill -9 -f run_in_terminal
  -pkill -9 -f mavproxy.py
  -pkill -9 -f ardurover
  -pkill -9 -f arducopter
  +killall $QUIET -SIGKILL sim_vehicle.py
  +killall $QUIET -SIGKILL mavproxy.py
  +killall $QUIET -SIGKILL ardurover
  +killall $QUIET -SIGKILL arducopter
  exit 0
  