Fix a segv when calling isConnected on an uninitialized socket.
Fix a segv when calling isConnected on an uninitialized socket.

	* include/libport/asio.hh (close, isConnected): Check if base_
	  before using it.
	(Socket): Initialize base_ to 0.
	(listenSSL): Wrap it if #ifndef LIBPORT_NO_SSL

aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport