Update dockerpty; stub it out in tests

Its current behaviour occasionally causes tests to hang; until this is
resolved, we'll stub it out. We weren't testing the output of 'run'
anyhow (though we should be).

requirements.txt

@@ -3,4 +3,4 @@ PyYAML==3.10
 requests==2.2.1
 texttable==0.8.1
 websocket-client==0.11.0
-dockerpty==0.1.0
+dockerpty==0.1.1

tests/integration/cli_test.py

@@ -102,7 +102,7 @@ class CLITestCase(DockerClientTestCase):
         self.assertEqual(old_ids, new_ids)
 
 
-    @patch('sys.stdout', new_callable=StringIO)
+    @patch('dockerpty.start')
     def test_run_with_links(self, mock_stdout):
         mock_stdout.fileno = lambda: 1
 
@@ -113,7 +113,7 @@ class CLITestCase(DockerClientTestCase):
         self.assertEqual(len(db.containers()), 1)
         self.assertEqual(len(console.containers()), 0)
 
-    @patch('sys.stdout', new_callable=StringIO)
+    @patch('dockerpty.start')
     def test_run_with_no_deps(self, mock_stdout):
         mock_stdout.fileno = lambda: 1
 
@@ -122,7 +122,7 @@ class CLITestCase(DockerClientTestCase):
         db = self.command.project.get_service('db')
         self.assertEqual(len(db.containers()), 0)
 
-    @patch('sys.stdout', new_callable=StringIO)
+    @patch('dockerpty.start')
     def test_run_does_not_recreate_linked_containers(self, mock_stdout):
         mock_stdout.fileno = lambda: 1