Drop DB deletion from test-esx

[lipingxue]

Details from this issue
#865

Our original plan was as follows:

introduce schema version in the DB
force DB deletion on test to hide "no versioned" -> "versioned" schema update
For further schema changes, support version to version in-place upgrade
so, the auth_db deletion was a temporary measure. It should not be needed anymore, we just need to make sure we do not have really stale DBs around

Actions:

we should drop the DB delete from test set (@liping)
if you still have od DB, remove it manyully per error message

This PR is used to track the first action which drop the DB delete from test set
Going forward, for further schema changes, we will support version to version in-place upgrade.
If incase user has any ancient DB(no version), he/she need to remove it manually.

[lipingxue]

Fixed #865