Add unnecessary record in mysql when I query quota with nonexistent tenant_id

[Liu Yang]

when I query quota with nonexistent tenant_id use trove cli, will add unnecessary record to mysql(database:trove, table:quota_usages).

e.g.

#trove quota-show errtenant
+-----------+--------+----------+-------+
| Resource | In Use | Reserved | Limit |
+-----------+--------+----------+-------+
| backups | 0 | 0 | 5 |
| instances | 0 | 0 | 5 |
| volumes | 0 | 0 | 100 |
+-----------+--------+----------+-------+

MariaDB [(none)]> use trove

MariaDB [trove]> select * from quota_usages where tenant_id="errtenant";
+--------------------------------------+---------------------+---------------------+-----------+--------+----------+-----------+
| id | created | updated | tenant_id | in_use | reserved | resource |
+--------------------------------------+---------------------+---------------------+-----------+--------+----------+-----------+
| 8a22d0e5-142f-4e55-995f-c8751e1cbcbb | 2017-02-15 11:55:25 | 2017-02-15 11:55:25 | errtenant | 0 | 0 | backups |
| 4a306e8d-33a5-44d8-9906-14ccf4d225da | 2017-02-15 11:55:25 | 2017-02-15 11:55:25 | errtenant | 0 | 0 | instances |
| 790efe51-3d57-4970-8acb-65b07c046996 | 2017-02-15 11:55:25 | 2017-02-15 11:55:25 | errtenant | 0 | 0 | volumes |
+--------------------------------------+---------------------+---------------------+-----------+--------+----------+-----------+
3 rows in set (0.00 sec)

It should not modify quota_usages in MySQL.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Liu Yang (<email address hidden>) on branch: master
Review: https://review.openstack.org/434598