fix inverted copy-threshold

IPython/zmq/session.py

@@ -567,7 +567,7 b' class Session(Configurable):'
         to_send = self.serialize(msg, ident)
         to_send.extend(buffers)
         longest = max([ len(s) for s in to_send ])
-        copy = (longest > self.copy_threshold)
+        copy = (longest < self.copy_threshold)
         
         if buffers and track and not copy:
             # only really track when we are doing zero-copy buffers

IPython/zmq/tests/test_session.py

@@ -146,6 +146,7 b' class TestSession(SessionTestCase):'
         """test tracking messages"""
         a,b = self.create_bound_pair(zmq.PAIR, zmq.PAIR)
         s = self.session
+        s.copy_threshold = 1
         stream = ZMQStream(a)
         msg = s.send(a, 'hello', track=False)
         self.assertTrue(msg['tracker'] is None)