undercloud: change upgrade steps

1) Rename the neutron DB at step 2 so Neutron has time to stop (during
step 1) and right after we stop mariadb, so no chance for any app to
access to old db.

2) Upgrade all rpms at step 3 like we do for other services. Step 1 was
way too early.

Change-Id: I34bdc0a9d575e5d1b8f3ce1e09c145cc34563a85

docker/services/database/mysql.yaml

@@ -262,7 +262,7 @@ outputs:
             fi
           become: true
           when:
-            - step|int == 1
+            - step|int == 2
             - {get_param: UndercloudUpgrade}
         - name: Stop and disable mysql service
           when:

docker/services/undercloud-upgrade.yaml

@@ -49,4 +49,4 @@ outputs:
           yum:
             name: '*'
             state: latest
-          when: step|int == 1
+          when: step|int == 3