Remove placement_database related options/code

The placement_database config options were added in Newton
but the actual code to use the options was reverted and is
not used.

Change-Id: Idd2edec3e98dbcd3361cf38434027ad16066ac46
Depends-On: https://review.openstack.org/541685
Related-Reviews: I31293ac4689630e4113588ab2c6373cf572b8f38
Closes-Bug: #1670419

test-install-nova.yml

@@ -70,10 +70,6 @@
       db_name: "{{ nova_api_galera_database }}"
       db_password: "{{ nova_api_container_mysql_password }}"
 
-    - include: create-grant-db.yml
-      db_name: "{{ nova_placement_galera_database }}"
-      db_password: "{{ nova_placement_container_mysql_password }}"
-
     - include: create-grant-db.yml
       db_name: "{{ nova_cell0_database }}"
       db_password: "{{ nova_api_container_mysql_password }}"

test-vars.yml

@@ -199,9 +199,6 @@ nova_discover_hosts_in_cells_interval: '-1'
 lxd_trust_password: "SuperSecrete"
 # nova placement vars
 nova_placement_service_password: "secrete"
-nova_placement_container_mysql_password: "SuperSecrete"
-nova_placement_galera_database: nova_placement
-nova_placement_galera_address: "{{ test_galera_host }}"
 nova_placement_service_publicuri: "http://{{ test_nova_api_placement_host }}:8780"
 nova_placement_service_publicurl: "{{ nova_placement_service_publicuri }}"
 nova_placement_service_adminuri: "http://{{ test_nova_api_placement_host }}:8780"