* Fixed Oracle new installer support, broken by r80957. This is a minimal patch and...

* Fixed Oracle new installer support, broken by r80957. This is a minimal patch and doesn't address the architectural issues.
** Moved the responsibility for calling setupSchemaVars() on install to the DatabaseInstaller subclass. This allows it to be called after setupDatabase() has completed, as required by Oracle and PostgreSQL.
** Fixed OracleInstaller::getConnection() so that it respects $this->useSysDBA correctly.
** In OracleInstaller, added some more variables to the list of schema vars, which are needed by user.sql and tables.sql
** In SearchOracle, specify the database name when calling ctx_ddl.sync_index(). This fixes a fatal error in the createMainpage step, caused by the schema name not being equal to the current user.

* In oracle/tables.sql, fixed a couple of indexes with missing table prefixes.
* Improved debugging output in DatabaseInstaller::getConnection() and Installer::createMainpage().
* In DatabaseBase::selectDB(), set $this->mDBname correctly, as in DatabaseMysql.