Fix duplicate TABLE_COLUMN condition in JDBCMetadataQueryDAO.findEndpoint()

[currenjin]

Fix duplicate TABLE_COLUMN condition in JDBCMetadataQueryDAO.findEndpoint()

• Add a unit test to verify that the fix works.
• Explain briefly why the bug exists and how to fix it.

findEndpoint() was adding the TABLE_COLUMN = ? WHERE condition twice and binding EndpointTraffic.INDEX_NAME as a parameter twice, due to a copy-paste error.

The generated SQL was:

select * from endpoint_traffic where table_name = ? and service_id = ? and table_name = ? ...

The second table_name = ? condition is redundant. All other methods in JDBCMetadataQueryDAO add the TABLE_COLUMN condition exactly once. The fix removes the duplicate condition and its corresponding parameter binding.

• If this pull request closes/resolves/fixes an existing issue, replace the issue number. Closes #.
• Update the CHANGES log.