update sample conf

Change-Id: Ic80e79ff412a0156a94b2992efb9ec9487b41a2c
Partial-Bug: 1293781
Related-Bug: 1233365

etc/keystone.conf.sample

@@ -839,12 +839,13 @@
 # dereferencing configured by your ldap.conf. (string value)
 #alias_dereferencing=default
 
+# Override the system's default referral chasing behavior for
+# queries. (boolean value)
+#chase_referrals=<None>
+
 # Search base for users. (string value)
 #user_tree_dn=<None>
 
-# Override the system's default referral chasing behavior for queries.
-#chase_referrals=<None>
-
 # LDAP search filter for users. (string value)
 #user_filter=<None>