[Hotfix] Typo in shiro_authentication.md

Remove one `ldapRealm.contextFactory.authenticationMechanism`
diff --git a/docs/setup/security/shiro_authentication.md b/docs/setup/security/shiro_authentication.md
index bda1ec4..6560d38 100644
--- a/docs/setup/security/shiro_authentication.md
+++ b/docs/setup/security/shiro_authentication.md
@@ -157,7 +157,6 @@
 # Ability to set ldap paging Size if needed default is 100
 ldapRealm.pagingSize = 200
 ldapRealm.authorizationEnabled = true
-ldapRealm.contextFactory.authenticationMechanism = simple
 ldapRealm.searchBase = dc=hadoop,dc=apache,dc=org
 ldapRealm.userSearchBase = dc=hadoop,dc=apache,dc=org
 ldapRealm.groupSearchBase = ou=groups,dc=hadoop,dc=apache,dc=org