Fixed toLowerCase bug in JDBC client

There was a bug in the JDBC client that was converting the whole
query to lower case while checking for the use keyword. This patch
fixes that bug

Change-Id: Ib7b4b6a1e383fec6dd7363c79768fb9bec54c61d
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/5327
Reviewed-by: Alex Leblang <alex.leblang@cloudera.com>
Tested-by: jenkins