TYPO3 Core

Scenario: the 1-2-3 install tool proces.

- on step 1, I choose PostgreSQL as my database system of choice
- the page reloads and displays an additional field for entering a database name
- when moving to step 2, I get a drop-down to select a database
- I stay with the same and move to step 3
- I get the following error message:

"ADONewConnection: Unable to load database driver '' "

This is because tx_dbal_installtool tries to retrieve the driver from GET/POST vars, line 94:

$driver = $instObj->INSTALL['localconf.php']['typo_db_driver'];

This seems unnecessary as - after step 1 - the driver has been saved successfully to the localconf.php in the DBAL configuration. I propose to get the driver from there instead of from a GET/POST variable.

It would also be good if there weren't 2 opportunities to enter a database name, because it is rather confusing IMO.

(issue imported from #M14457)