Allow container name property from sparse list

When listing containers with `sparse=True` the container's name property
does not work because there is no 'Name' attribue on the object returned
by the Docker API. Instead the name is in the 'Names' attribute.

Signed-off-by: Stuart Thomson <stuartwthomson@live.co.uk>

docker/models/containers.py

@@ -28,6 +28,8 @@ class Container(Model):
         """
         if self.attrs.get('Name') is not None:
             return self.attrs['Name'].lstrip('/')
+        if self.attrs.get('Names') is not None:
+            return self.attrs['Names'][0].lstrip('/')
 
     @property
     def image(self):

tests/integration/models_containers_test.py

@@ -210,7 +210,7 @@ class ContainerCollectionTest(BaseIntegrationTest):
     def test_list_sparse(self):
         client = docker.from_env(version=TEST_API_VERSION)
         container_id = client.containers.run(
-            "alpine", "sleep 300", detach=True).id
+            "alpine", "sleep 300", detach=True, name='a_container').id
         self.tmp_containers.append(container_id)
         containers = [c for c in client.containers.list(sparse=True) if c.id ==
                       container_id]
@@ -220,6 +220,7 @@ class ContainerCollectionTest(BaseIntegrationTest):
         assert container.attrs['Image'] == 'alpine'
         assert container.status == 'running'
         assert container.image == client.images.get('alpine')
+        assert container.name == 'a_container'
         with pytest.raises(docker.errors.DockerException):
             container.labels