Fix grafana database creation

Kolla use kolla_toolbox container to interact
with the database.
Grafana fails to deploy if mysql-python is not installed
in the host.

Change-Id: I033f1828ff027532de9be94aaf7dee6dbeab8fb6
Closes-Bug: #1661646

ansible/roles/grafana/tasks/bootstrap.yml

@@ -1,6 +1,8 @@
 ---
 - name: Creating grafana database
-  mysql_db:
+  kolla_toolbox:
+    module_name: mysql_db
+    module_args:
       login_host: "{{ database_address }}"
       login_port: "{{ database_port }}"
       login_user: "{{ database_user }}"
@@ -10,7 +12,9 @@
   delegate_to: "{{ groups['grafana'][0] }}"
 
 - name: Creating grafana database user and setting permissions
-  mysql_user:
+  kolla_toolbox:
+    module_name: mysql_user
+    module_args:
       login_host: "{{ database_address }}"
       login_port: "{{ database_port }}"
       login_user: "{{ database_user }}"