MDL-49276 config-dist: Removed legacy config options

Both $CFG->logsql and $CFG->dblogerror had no use in moodle core
since ages ago (just the former had one use for nothing). Good time
to get rid of both as they are 100% misleading.

lib/setup.php

@@ -683,11 +683,6 @@ if (!defined('NO_UPGRADE_CHECK') and isset($CFG->upgraderunning)) {
     }
 }
 
-// Turn on SQL logging if required
-if (!empty($CFG->logsql)) {
-    $DB->set_logging(true);
-}
-
 // enable circular reference collector in PHP 5.3,
 // it helps a lot when using large complex OOP structures such as in amos or gradebook
 if (function_exists('gc_enable')) {