daemon/automount: Ignore SIGWINCH

Running the daemon in the foreground, the following annoying message is
shown a lot.

> statemachine:1540: got unexpected signal 28!

Here the number 28 means `SIGWINCH`.

> Window size change. This is generated on some systems (including GNU)
> when the terminal driver's record of the number of rows and columns on
> the screen is changed. The default action is to ignore it.
>
> If a program does full-screen display, it should handle SIGWINCH. When
> the signal arrives, it should fetch the new screen size and reformat
> its display accordingly.

[1] http://www.delorie.com/gnu/docs/glibc/libc_478.html

daemon/automount.c

@@ -1536,6 +1536,9 @@ static void *statemachine(void *arg)
 			do_hup_signal(master_list);
 			break;
 
+		case SIGWINCH:
+			continue;
+
 		default:
 			logerr("got unexpected signal %d!", sig);
 			continue;