merged pex fix from RC_0_16

ChangeLog

@@ -9,6 +9,7 @@
 	* fix uTP edge case where udp socket buffer fills up
 	* fix nagle implementation in uTP
 
+	* improve peers exchanged over PEX
 	* fixed rare crash in ut_metadata extension
 	* fixed files checking issue
 	* added missing pop_alerts() to python bindings

src/ut_pex.cpp

@@ -78,6 +78,7 @@ namespace libtorrent { namespace
 		if (!p.is_outgoing() && !p.received_listen_port()) return false;
 		// don't send out peers that we haven't successfully connected to
 		if (p.is_connecting()) return false;
+		if (p.in_handshake()) return false;
 		return true;
 	}