Remove cinder v1 artifacts from code base

Following Tempest's removal of Cinder v1 [0], Patrole should do
the same by removing any support for v1 from the code base.

[0] https://review.openstack.org/#/c/446233/

Change-Id: Ia27d7b9c19f7c53dd5605dea8f77a02251a0ab38
diff --git a/patrole_tempest_plugin/tests/api/volume/rbac_base.py b/patrole_tempest_plugin/tests/api/volume/rbac_base.py
index ccadad1..c78a3e4 100644
--- a/patrole_tempest_plugin/tests/api/volume/rbac_base.py
+++ b/patrole_tempest_plugin/tests/api/volume/rbac_base.py
@@ -41,8 +41,6 @@
         cls.rbac_utils.switch_role(cls, toggle_rbac_role=False)
 
         version_checker = {
-            1: [cls.os_primary.volume_hosts_client,
-                cls.os_primary.volume_types_client],
             2: [cls.os_primary.volume_hosts_v2_client,
                 cls.os_primary.volume_types_v2_client],
             3: [cls.os_primary.volume_hosts_v2_client,