Modified RdbmsCatalogue to use autocommitMode default of Stmt::executeQuery()...

Modified RdbmsCatalogue to use autocommitMode default of Stmt::executeQuery() and Stmt::executeNonQuery()

Please note that OracleCatalogue::filesWrittenToTape() now updates the TAPE
table row with AUTOCOMMIT_ON before going on to handle the individual file
entries.  This can be improved when Conn:setAutocommit() becomes available.