fix Config merge with project config

SE/se-lib/Config.php

@@ -66,7 +66,7 @@ class Config {
 				if (file_exists("{$projPath}/config.php")) {
 					$projConfig = include "{$projPath}/config.php";
 					if (!empty($projConfig)) {
-						$_main_config = array_merge($_main_config, $projConfig);
+						$_main_config = array_merge($_main_config ? $_main_config : [], $projConfig);
 					}
 				}
 			}