oracle driver ignores driver options

The driver options array passed in in https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/OCI8/Driver.php#L36 is ignored and options like sessionMode, persistent and pooled are taken from $params.

The adapters in doctrine currently treat $driverOptions differently:

• Oracle ignores them and intead uses the $params array: https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/OCI8/Driver.php#L44
• MySQL (PDO) uses them: https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/PDOMySql/Driver.php#L44
• PgSqL (PDO) uses them: https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/PDOPgSql/Driver.php#L45
• MySQLi uses the options https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/Mysqli/MysqliConnection.php#L62 and ultimately https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/Mysqli/MysqliConnection.php#L214
• Sqlite (PDO) uses them, but removes userDefinedFunctions: https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/PDOSqlite/Driver.php#L59
• SQLSrv uses it as the array used for the actual connection: https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/SQLSrv/Driver.php#L44 and oltimately https://github.com/doctrine/dbal/blob/master/lib/Doctrine/DBAL/Driver/SQLSrv/SQLSrvConnection.php#L55

So I think merging the db options with the params array is a good enough solution. It is what we are planning to do as a workaround until we update to latest doctrine: https://github.com/owncloud/core/pull/23938

Opinions?