Concurrent lock still has some minor issues, don't enable it by default.

git-svn-id: http://svn.code.sf.net/p/itop/code/trunk@3772 a333f486-631f-4898-b8df-5754b55c2be0

core/config.class.inc.php

@@ -845,10 +845,10 @@ class Config
 		'concurrent_lock_enabled' => array(
 			'type' => 'bool',
 			'description' => 'Whether or not to activate the locking mechanism in order to prevent concurrent edition of the same object.',
-			'default' => true,
+			'default' => false,
 			'value' => '',
 			'source_of_value' => '',
-			'show_in_conf_sample' => true,
+			'show_in_conf_sample' => false,
 		),
 		'concurrent_lock_expiration_delay' => array(
 			'type' => 'integer',