Prevent socket leak in ThreadSocketHandler.

When we are over our outbound limit ThreadSocketHandler would try to
keep the connection if the peer was addnoded.

This didn't actually work for two reasons: It didn't actually run
the accept code due to mistaken code flow, and because we have a
limited number of outbound semaphores it couldn't actually use the
connection.

Instead it leaked the socket, which might have caused issue #4034.

This patch just takes out the non-functioning white-listing for now.