title: Jaybird 2.2.4 NestedTransactionNotSupportedException: JpaDialect does not support savepoints
body: <p>Using @Transactional(value ="erpJPA",propagation=Propagation.NESTED )
  i have the exception </p>
  
  <pre><code>    Caused by: org.springframework.transaction.NestedTransactionNotSupportedException: 
  JpaDialect does not support savepoints - check your JPA provider's capabilities
  </code></pre>
  
  <p>Doesn't firebird support Nested Transaction from version 1.5?</p>