If the $db_type variable has no value then don't write the config.lua script.

core/databases/app_defaults.php

@@ -98,6 +98,7 @@ if ($domains_processed == 1) {
 			}
 
 		//config.lua
+			if (strlen($db_type) > 0) {
 				if (is_dir("/etc/fusionpbx")){
 					$config = "/etc/fusionpbx/config.lua";
 				} elseif (is_dir("/usr/local/etc/fusionpbx")){
@@ -169,5 +170,6 @@ if ($domains_processed == 1) {
 				unset($tmp);
 				fclose($fout);
 			}
+	}
 }
 ?>