Use modern pyzmq attribute cleverness

IPython/kernel/channels.py

@@ -32,22 +32,22 b' class InvalidPortNumber(Exception):'
 def make_shell_socket(context, identity, address):
     socket = context.socket(zmq.DEALER)
     socket.linger = 1000
-    socket.setsockopt(zmq.IDENTITY, identity)
+    socket.identity = identity
     socket.connect(address)
     return socket
 
 def make_iopub_socket(context, identity, address):
     socket = context.socket(zmq.SUB)
     socket.linger = 1000
-    socket.setsockopt(zmq.SUBSCRIBE,b'')
-    socket.setsockopt(zmq.IDENTITY, identity)
+    socket.subscribe = b''
+    socket.identity = identity
     socket.connect(address)
     return socket
 
 def make_stdin_socket(context, identity, address):
     socket = context.socket(zmq.DEALER)
     socket.linger = 1000
-    socket.setsockopt(zmq.IDENTITY, identity)
+    socket.identity = identity
     socket.connect(address)
     return socket