[ci skip] Change some log messages' level

'Class Loaded' type of messages flood log files when
log_threshold is set to 2 (debug). They're now logged
as 'info' level.

This is manually applying PR #1528, which was created
to do the same thing, but became outdated.
diff --git a/system/core/Hooks.php b/system/core/Hooks.php
index 429d6bc..a55b38a 100644
--- a/system/core/Hooks.php
+++ b/system/core/Hooks.php
@@ -88,8 +88,7 @@
 	public function __construct()
 	{
 		$CFG =& load_class('Config', 'core');
-
-		log_message('debug', 'Hooks Class Initialized');
+		log_message('info', 'Hooks Class Initialized');
 
 		// If hooks are not enabled in the config file
 		// there is nothing else to do