fix generic_includes.php returning error "Undefined variable in /var/…

…www/loris/tools/generic_includes.php on line 28" - 25 branch (aces#9318)

This fixes the script `generic_includes.php` that calls the $DB variable
before it is defined when calling LorisInstance.

Without this fix, anything calling `generic_includes.php` will trigger
the following error:
```
Undefined variable in /var/www/loris/tools/generic_includes.php on line 28
PHP Fatal error:  Uncaught TypeError: LORIS\\LorisInstance::__construct(): Argument #1 ($db) must be of type Database, null given, called in /var/www/loris/tools/generic_includes.php on line 27
```

tools/generic_includes.php

@@ -24,6 +24,7 @@
 $client->makeCommandLine();
 $client->initialize($configFile);
 $config        = NDB_Config::singleton();
+$DB            = NDB_Factory::singleton()->database();
 $lorisInstance = new \LORIS\LorisInstance(
     $DB,
     $config,
@@ -32,4 +33,3 @@
         __DIR__ . "/../modules/",
     ],
 );
-$DB            = $lorisInstance->getDatabaseConnection();