fix case typo in auth source example file

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@1735 44740490-163a-0410-bde0-09ae8108e29a

config-templates/authsources.php

@@ -81,7 +81,7 @@ $config = array(
 		 * The entity ID of this SP.
 		 * Can be NULL/unset, in which case an entity ID is generated based on the metadata URL.
 		 */
-		'entityId' => NULL,
+		'entityid' => NULL,
 
 		/*
 		 * The entity ID of the IdP this should SP should contact.