Fixed race condition when closing redundant sockets.

When more than one invitation socket is opened, Alice should pick which one to use and Bob should use whichever one Alice picks. This fixes a race condition where each party picked a different socket and closed the other.

briar-desktop/src/org/briarproject/plugins/modem/ModemPlugin.java

@@ -154,7 +154,7 @@ class ModemPlugin implements DuplexPlugin, Modem.Callback {
 	}
 
 	public DuplexTransportConnection createInvitationConnection(PseudoRandom r,
-			long timeout) {
+			long timeout, boolean alice) {
 		throw new UnsupportedOperationException();
 	}