fix: guard port_close in nova_watcher terminate (#376)

Author: Taure

src/nova_watcher.erl

@@ -185,11 +185,9 @@ handle_info(_Info, State) ->
 %%--------------------------------------------------------------------
 -spec terminate(Reason :: normal | shutdown | {shutdown, term()} | term(),
                 State :: term()) -> any().
-terminate(_Reason, #state{process_refs = Refs}) ->
-    %% Clean up the ports
-    lists:foreach(fun(PortRef) ->
-                          erlang:port_close(PortRef)
-                  end, Refs),
+terminate(_Reason, _State) ->
+    %% Ports opened with open_port/2 are linked to this process
+    %% and automatically closed when it exits.
     ok.
 
 %%--------------------------------------------------------------------