Remove Service.start_or_create_containers()

It's only used in a single test method.

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

tests/integration/service_test.py

@@ -501,10 +501,10 @@ class ServiceTest(DockerClientTestCase):
             ],
         })
 
-    def test_start_with_image_id(self):
+    def test_create_with_image_id(self):
         # Image id for the current busybox:latest
         service = self.create_service('foo', image='8c2e06607696')
-        self.assertTrue(service.start_or_create_containers())
+        service.create_container()
 
     def test_scale(self):
         service = self.create_service('web')