Issue #502: Kundera JPA query for oracle DB - table name prefixed with UNDERSCORE

This is a fix for
https://github.com/impetus-opensource/Kundera/issues/502.
Removing the UNDERSCORE prefix while generating the select queries. This
is tested for both MySql and Oracle 11g servers.
Adding UNDERSCORE as suffix instead of prefix. Works with both MySQL and Oracle

This is a fix for
https://github.com/impetus-opensource/Kundera/issues/502
Merge pull request #504 from bcwajapey/kundera-oracle11g

Issue #502: Kundera JPA query for oracle DB - table name prefixed with U...