Cleaning up MultiKernelManager test and adding linger=0 to shell.

We are finding that the tests for MultiKernelManager hang because
linger default to oo in the shell channel. By setting it to 0,
the tests pass fine. Last night, we thought it was particular to
the ipc transport, but now the hang occurs for any transport.

IPython/frontend/html/notebook/tests/test_kernelsession.py

@@ -31,37 +31,30 b' class TestKernelManager(TestCase):'
         km.shutdown_kernel(kid)
         self.assertTrue(not kid in km)
 
-    def test_km_tcp(self):
-        km = self._get_tcp_km()
-        self._run_lifecycle(km)
-
-    def test_km_ipc(self):
-        km = self._get_ipc_km()
-        self._run_lifecycle(km)
-
-    def test_tcp_cinfo(self):
-        km = self._get_tcp_km()
+    def _run_cinfo(self, km, transport, ip):
         kid = km.start_kernel()
         k = km.get_kernel(kid)
         cinfo = km.get_connection_info(kid)
-        self.assertEqual('tcp', cinfo['transport'])
-        self.assertEqual('127.0.0.1', cinfo['ip'])
+        self.assertEqual(transport, cinfo['transport'])
+        self.assertEqual(ip, cinfo['ip'])
         self.assertTrue('stdin_port' in cinfo)
         self.assertTrue('iopub_port' in cinfo)
         self.assertTrue('shell_port' in cinfo)
         self.assertTrue('hb_port' in cinfo)
         km.shutdown_kernel(kid)
 
+    def test_km_tcp(self):
+        km = self._get_tcp_km()
+        self._run_lifecycle(km)
+    
+    def test_tcp_cinfo(self):
+        km = self._get_tcp_km()
+        self._run_cinfo(km, 'tcp', '127.0.0.1')
+
+    def test_km_ipc(self):
+        km = self._get_ipc_km()
+        self._run_lifecycle(km)
+    
     def test_ipc_cinfo(self):
         km = self._get_ipc_km()
-        kid = km.start_kernel()
-        k = km.get_kernel(kid)
-        cinfo = km.get_connection_info(kid)
-        self.assertEqual('ipc', cinfo['transport'])
-        self.assertEqual('test', cinfo['ip'])
-        self.assertTrue('stdin_port' in cinfo)
-        self.assertTrue('iopub_port' in cinfo)
-        self.assertTrue('shell_port' in cinfo)
-        self.assertTrue('hb_port' in cinfo)
-        km.shutdown_kernel(kid)
-
+        self._run_cinfo(km, 'ipc', 'test')

IPython/zmq/kernelmanager.py

@@ -201,6 +201,7 b' class ShellChannel(ZMQSocketChannel):'
         """The thread's main activity.  Call start() instead."""
         self.socket = self.context.socket(zmq.DEALER)
         self.socket.setsockopt(zmq.IDENTITY, self.session.bsession)
+        self.socket.linger = 0
         self.socket.connect(self.address)
         self.stream = zmqstream.ZMQStream(self.socket, self.ioloop)
         self.stream.on_recv(self._handle_recv)