Enable rgw_swift_enforce_content_length

Currently test_list_containers tempest tests[1] would be failed.
It is becuase accept-ranges header does not exist. See ceph bug[2].

Rgw_swift_enforce_content_length assures Content-Length and
Accept-Ranges in dynamically generated account & container listings.

[1] tempest.api.object_storage.test_account_services.AccountTest.test_list_containers
[2] http://tracker.ceph.com/issues/21554
Related-Bug: #1783456

Change-Id: I9b5fcc361f0bc0e521302d2df1974aabf6f4a7e7

ansible/roles/ceph/templates/ceph.conf.j2

@@ -46,5 +46,6 @@ log file = /var/log/kolla/ceph/client.radosgw.gateway.log
 {% if ceph_rgw_compatibility | bool %}
 rgw_swift_url_prefix = "/"
 rgw_enable_apis = swift,swift_auth,admin
+rgw_swift_enforce_content_length = true
 {% endif %}
 {% endif %}