Do not send error on closed connection.

neo/lib/handler.py

@@ -54,22 +54,27 @@ class EventHandler(object):
             args = packet.decode() or ()
             method(conn, *args, **kw)
         except UnexpectedPacketError, e:
+            if not conn.isClosed():
                 self.__unexpectedPacket(conn, packet, *e.args)
         except PacketMalformedError:
+            if not conn.isClosed():
                 neo.lib.logging.error('malformed packet from %r', conn)
                 conn.notify(Packets.Notify('Malformed packet: %r' % (packet, )))
                 conn.abort()
                 # self.peerBroken(conn)
         except BrokenNodeDisallowedError:
+            if not conn.isClosed():
                 conn.answer(Errors.BrokenNode('go away'))
                 conn.abort()
         except NotReadyError, message:
+            if not conn.isClosed():
                 if not message.args:
                     message = 'Retry Later'
                 message = str(message)
                 conn.answer(Errors.NotReady(message))
                 conn.abort()
         except ProtocolError, message:
+            if not conn.isClosed():
                 message = str(message)
                 conn.answer(Errors.ProtocolError(message))
                 conn.abort()