make odbc driver ping to be Integraty and check DBserver's availablity when setup backend connection

Software Environment:
OpenLooKeng version (source or binary): NA

OS platform & distribution (eg., Linux Ubuntu 16.04): NA

Java version:

Describe the current behavior

1. Current ping action actually end in gateway, so even if DB server is down, ping by ODBC API will show no problem.
2. Current gateway set up backend connection to through JDBC API and return sucess to ODBC driver, without checking if DBserver is available. In case of DBserver dead or not enough permision, should return erro message to ODBC driver.

Describe the expected behavior

1. Ping action actually ping the DB server, and response real DB server state to ODBC driver.
2. base on 1, for backend connection setup, return success if DBserver is available, return failure in other case.

Steps to reproduce the issue
Lanch ping action by ODBC API
test the cases of DB server active and shutdown

Related log/screenshots
NA

Special notes for this issue
NA