Change Solum keystone v2 to v3

Solum default use keystone v3
https://github.com/openstack/solum/blob/master/solum/common/solum_keystoneclient.py#L40

Change-Id: I85f73e495ad800f614850cd27fa0e7153dcfc685

ansible/roles/solum/templates/solum.conf.j2

@@ -42,7 +42,7 @@ connection = mysql+pymysql://{{ solum_database_user }}:{{ solum_database_passwor
 max_retries = -1
 
 [keystone_authtoken]
-auth_uri = {{ internal_protocol }}://{{ kolla_internal_fqdn }}:{{ keystone_public_port }}/v2.0
+auth_uri = {{ internal_protocol }}://{{ kolla_internal_fqdn }}:{{ keystone_public_port }}
 auth_url = {{ admin_protocol }}://{{ kolla_internal_fqdn }}:{{ keystone_admin_port }}
 auth_type = password
 project_domain_id = default