Description of problem:
If in addition to setting V1 to false in cinder.conf we delete the endpoint for cinder, Horizon stops showing the Volumes tab.

Version-Release number of selected component (if applicable):

python-django-horizon-8.0.1-6.el7ost.src.rpm

How reproducible:
delete cinder endpoint v1

Steps to Reproduce:
[root@rhosp8 ~(keystone_admin)]# keystone service-list
/usr/lib/python2.7/site-packages/keystoneclient/shell.py:64: DeprecationWarning: The keystone CLI is deprecated in favor of python-openstackclient. For a Python library, continue using python-keystoneclient.
  'python-keystoneclient.', DeprecationWarning)
/usr/lib/python2.7/site-packages/keystoneclient/v2_0/client.py:145: DeprecationWarning: Constructing an instance of the keystoneclient.v2_0.client.Client class without a session is deprecated as of the 1.7.0 release and may be removed in the 2.0.0 release.
  'the 2.0.0 release.', DeprecationWarning)
/usr/lib/python2.7/site-packages/keystoneclient/v2_0/client.py:147: DeprecationWarning: Using the 'tenant_name' argument is deprecated in version '1.7.0' and will be removed in version '2.0.0', please use the 'project_name' argument instead
  super(Client, self).__init__(**kwargs)
/usr/lib/python2.7/site-packages/debtcollector/renames.py:43: DeprecationWarning: Using the 'tenant_id' argument is deprecated in version '1.7.0' and will be removed in version '2.0.0', please use the 'project_id' argument instead
  return f(*args, **kwargs)
/usr/lib/python2.7/site-packages/keystoneclient/httpclient.py:376: DeprecationWarning: Constructing an HTTPClient instance without using a session is deprecated as of the 1.7.0 release and may be removed in the 2.0.0 release.
  'the 2.0.0 release.', DeprecationWarning)
+----------------------------------+------------+--------------+--------------------------------+
|                id                |    name    |     type     |          description           |
+----------------------------------+------------+--------------+--------------------------------+
| 1393f0aad2b740c0aa618d2a33496250 | ceilometer |   metering   |   Openstack Metering Service   |
| 6c0a114dff1f4efa91d3c4ba7fd0c51b |   cinder   |    volume    |         Cinder Service         |
| ec0db3ef192645d2ae2963be89888fa2 |  cinderv2  |   volumev2   |       Cinder Service v2        |
| 1b4df1aa2ed54425a3f8ea89eddb8631 |   glance   |    image     |    OpenStack Image Service     |
| 55ccf5fb0dbf4820a7ab0cff4ed6bd9d |  keystone  |   identity   |   OpenStack Identity Service   |
| 5f7e4465298d4fee822d716e439708ac |  neutron   |   network    |   Neutron Networking Service   |
| c019af4a85f543c38e3b8ebe33353907 |    nova    |   compute    |   Openstack Compute Service    |
| 651dad2835a448d492c23eee82c60097 |  nova_ec2  |     ec2      |          EC2 Service           |
| 870b61f626fe43928f72207db457e496 |   novav3   |  computev3   |  Openstack Compute Service v3  |
| aa9c801467334510b2eef1548d3482ee |   swift    | object-store | Openstack Object-Store Service |
+----------------------------------+------------+--------------+--------------------------------+
[root@rhosp8 ~(keystone_admin)]# keystone service-delete 6c0a114dff1f4efa91d3c4ba7fd0c51b
/usr/lib/python2.7/site-packages/keystoneclient/shell.py:64: DeprecationWarning: The keystone CLI is deprecated in favor of python-openstackclient. For a Python library, continue using python-keystoneclient.
  'python-keystoneclient.', DeprecationWarning)
/usr/lib/python2.7/site-packages/keystoneclient/v2_0/client.py:145: DeprecationWarning: Constructing an instance of the keystoneclient.v2_0.client.Client class without a session is deprecated as of the 1.7.0 release and may be removed in the 2.0.0 release.
  'the 2.0.0 release.', DeprecationWarning)
/usr/lib/python2.7/site-packages/keystoneclient/v2_0/client.py:147: DeprecationWarning: Using the 'tenant_name' argument is deprecated in version '1.7.0' and will be removed in version '2.0.0', please use the 'project_name' argument instead
  super(Client, self).__init__(**kwargs)
/usr/lib/python2.7/site-packages/debtcollector/renames.py:43: DeprecationWarning: Using the 'tenant_id' argument is deprecated in version '1.7.0' and will be removed in version '2.0.0', please use the 'project_id' argument instead
  return f(*args, **kwargs)
/usr/lib/python2.7/site-packages/keystoneclient/httpclient.py:376: DeprecationWarning: Constructing an HTTPClient instance without using a session is deprecated as of the 1.7.0 release and may be removed in the 2.0.0 release.
  'the 2.0.0 release.', DeprecationWarning)
[root@rhosp8 ~(keystone_admin)]# keystone service-list
/usr/lib/python2.7/site-packages/keystoneclient/shell.py:64: DeprecationWarning: The keystone CLI is deprecated in favor of python-openstackclient. For a Python library, continue using python-keystoneclient.
  'python-keystoneclient.', DeprecationWarning)
/usr/lib/python2.7/site-packages/keystoneclient/v2_0/client.py:145: DeprecationWarning: Constructing an instance of the keystoneclient.v2_0.client.Client class without a session is deprecated as of the 1.7.0 release and may be removed in the 2.0.0 release.
  'the 2.0.0 release.', DeprecationWarning)
/usr/lib/python2.7/site-packages/keystoneclient/v2_0/client.py:147: DeprecationWarning: Using the 'tenant_name' argument is deprecated in version '1.7.0' and will be removed in version '2.0.0', please use the 'project_name' argument instead
  super(Client, self).__init__(**kwargs)
/usr/lib/python2.7/site-packages/debtcollector/renames.py:43: DeprecationWarning: Using the 'tenant_id' argument is deprecated in version '1.7.0' and will be removed in version '2.0.0', please use the 'project_id' argument instead
  return f(*args, **kwargs)
/usr/lib/python2.7/site-packages/keystoneclient/httpclient.py:376: DeprecationWarning: Constructing an HTTPClient instance without using a session is deprecated as of the 1.7.0 release and may be removed in the 2.0.0 release.
  'the 2.0.0 release.', DeprecationWarning)
+----------------------------------+------------+--------------+--------------------------------+
|                id                |    name    |     type     |          description           |
+----------------------------------+------------+--------------+--------------------------------+
| 1393f0aad2b740c0aa618d2a33496250 | ceilometer |   metering   |   Openstack Metering Service   |
| ec0db3ef192645d2ae2963be89888fa2 |  cinderv2  |   volumev2   |       Cinder Service v2        |
| 1b4df1aa2ed54425a3f8ea89eddb8631 |   glance   |    image     |    OpenStack Image Service     |
| 55ccf5fb0dbf4820a7ab0cff4ed6bd9d |  keystone  |   identity   |   OpenStack Identity Service   |
| 5f7e4465298d4fee822d716e439708ac |  neutron   |   network    |   Neutron Networking Service   |
| c019af4a85f543c38e3b8ebe33353907 |    nova    |   compute    |   Openstack Compute Service    |
| 651dad2835a448d492c23eee82c60097 |  nova_ec2  |     ec2      |          EC2 Service           |
| 870b61f626fe43928f72207db457e496 |   novav3   |  computev3   |  Openstack Compute Service v3  |
| aa9c801467334510b2eef1548d3482ee |   swift    | object-store | Openstack Object-Store Service |
+----------------------------------+------------+--------------+--------------------------------+

Actual results:
Volumes tab goes missing in Horizon

Expected results:
cinder v1 endpoint is deleted and we end up using cinderV2 only.

Additional info:
this was tested on RHEL 7.2 and 7.3