IPv4 listen socket fix

- on OpenBSD, you can't have a socket that supports both IPv4 and IPv6.
  This allows handling for this error, and then it will try IPv4 only,
  just like for other similar errors.

src/class_singleListener.py

@@ -91,7 +91,8 @@ class singleListener(threading.Thread, StoppableThread):
                 e.args[0] in (errno.EAFNOSUPPORT,
                               errno.EPFNOSUPPORT,
                               errno.EADDRNOTAVAIL,
-                              errno.ENOPROTOOPT)):
+                              errno.ENOPROTOOPT,
+                              errno.EINVAL)):
                 sock = self._createListenSocket(socket.AF_INET)
             else:
                 raise