mariadb: reasonable timing for readinessProbe

Give mariadb time to start up and probe only as much as needed.  This
avoids premature health warnings.

Change-Id: I5427cb26dc6a788123bdfac925e6d94321aabb1f

mariadb/templates/statefulset.yaml

@@ -64,6 +64,9 @@ spec:
                   name: mariadb-db-root-password
                   key: MYSQL_ROOT_PASSWORD
           readinessProbe:
+            initialDelaySeconds: 60
+            periodSeconds: 30
+            timeoutSeconds: 3
             exec:
               command:
                 - /tmp/readiness.sh