Cancel timer if it exists

c_src/farmbot-arduino-firmware

@@ -1 +1 @@
-Subproject commit d65960761703b835f067828be216c88715d2311b
+Subproject commit 70dc10e8c5c560ca75f846816364ce04a78a3379

lib/farmbot/firmware/firmware.ex

@@ -555,6 +555,7 @@ defmodule Farmbot.Firmware do
   end
 
   defp do_reply(state, reply) do
+    maybe_cancel_timer(state.timer)
     case state.current do
       %Current{fun: :emergency_lock, from: from} ->
         :ok = GenServer.reply from, {:error, :emergency_lock}