Implemet setNull. (firebird-sdbc)

Change-Id: I9fd53a5e8b5d1dba467fa8064f9f2ea1b93f26df
diff --git a/connectivity/source/drivers/firebird/PreparedStatement.cxx b/connectivity/source/drivers/firebird/PreparedStatement.cxx
index 00f7b0e..2c59931 100644
--- a/connectivity/source/drivers/firebird/PreparedStatement.cxx
+++ b/connectivity/source/drivers/firebird/PreparedStatement.cxx
@@ -323,6 +323,16 @@ Reference< XResultSet > SAL_CALL OPreparedStatement::executeQuery()
}

//----- XParameters -----------------------------------------------------------
void SAL_CALL OPreparedStatement::setNull(sal_Int32 nIndex, sal_Int32 nSqlType)
    throw(SQLException, RuntimeException)
{
    (void) nSqlType;
    MutexGuard aGuard( m_pConnection->getMutex() );
    checkDisposed(OStatementCommonBase_Base::rBHelper.bDisposed);

    setParameterNull(nIndex, true);
}

void SAL_CALL OPreparedStatement::setBoolean(sal_Int32 nIndex, sal_Bool x)
    throw(SQLException, RuntimeException)
{
@@ -458,16 +468,6 @@ void SAL_CALL OPreparedStatement::setFloat( sal_Int32 parameterIndex, float x ) 
}
// -------------------------------------------------------------------------

void SAL_CALL OPreparedStatement::setNull( sal_Int32 parameterIndex, sal_Int32 sqlType ) throw(SQLException, RuntimeException)
{
    (void) parameterIndex;
    (void) sqlType;
    ::osl::MutexGuard aGuard( m_pConnection->getMutex() );
    checkDisposed(OStatementCommonBase_Base::rBHelper.bDisposed);

}
// -------------------------------------------------------------------------

void SAL_CALL OPreparedStatement::setClob( sal_Int32 parameterIndex, const Reference< XClob >& x ) throw(SQLException, RuntimeException)
{
    (void) parameterIndex;