Update assert in test_create_with_restart_policy

In https://github.com/docker/docker/pull/30870 a new
error message is displayed if the container is restarting.

To make "test_create_with_restart_policy" pass against the
above change, the test checks that the error message contains
"You cannot remove " instead of
"You cannot remove a running container"
Signed-off-by: Boaz Shuster <ripcurld.github@gmail.com>

tests/integration/api_container_test.py

@@ -122,7 +122,7 @@ class CreateContainerTest(BaseAPIIntegrationTest):
             self.client.remove_container(id)
         err = exc.exception.explanation
         self.assertIn(
-            'You cannot remove a running container', err
+            'You cannot remove ', err
         )
         self.client.remove_container(id, force=True)