monitor: use after free in do_wav_capture()

use after free in do_wav_capture() on the error path.
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

monitor.c

@@ -2509,8 +2509,9 @@ static void do_wav_capture(Monitor *mon, const QDict *qdict)
     nchannels = has_channels ? nchannels : 2;
 
     if (wav_start_capture (s, path, freq, bits, nchannels)) {
-        monitor_printf(mon, "Faied to add wave capture\n");
+        monitor_printf(mon, "Failed to add wave capture\n");
         qemu_free (s);
+        return;
     }
     QLIST_INSERT_HEAD (&capture_head, s, entries);
 }