Hard reset Z-Wave module on Z/IP Gateway exit (#888)

If a reset function is provided in Grizzly's startup options, reset the
Z-Wave module when Z/IP Gateway exits to try to resolve cases where the
module has locked up.

lib/grizzly/zipgateway/supervisor.ex

@@ -200,6 +200,16 @@ defmodule Grizzly.ZIPGateway.Supervisor do
       %{exit_status: status}
     )
 
+    grizzly_opts = Grizzly.options()
+    reset_zwave_module(grizzly_opts)
+
     :error_exit_status
   end
+
+  @spec reset_zwave_module(Options.t()) :: :ok
+  defp reset_zwave_module(%Options{zwave_firmware: opts}) do
+    if is_function(opts[:module_reset_fun], 0), do: opts.module_reset_fun.()
+
+    :ok
+  end
 end