FIX: `unicorn_launcher` should shut down unicorn gracefully.

config/unicorn_launcher

@@ -18,7 +18,7 @@ function on_reload()
   sleep 10
   curl $LOCAL_WEB &> /dev/null
   NEW_UNICORN_PID=`ps -f --ppid $UNICORN_PID | grep unicorn | grep -v worker | awk '{ print $2 }'`
-  kill $UNICORN_PID
+  kill -s QUIT $UNICORN_PID
   echo "Old pid is: $UNICORN_PID New pid is: $NEW_UNICORN_PID"
   UNICORN_PID=$NEW_UNICORN_PID
 }