Add SNMPv3 USM example (commented out)

src/etc/snmpd.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: snmpd.conf,v 1.2 2008/01/30 10:21:05 reyk Exp $
+# $OpenBSD: snmpd.conf,v 1.3 2012/09/18 09:57:49 reyk Exp $
 
 listen_addr="127.0.0.1"
 
@@ -17,3 +17,8 @@ system services 74
 # Provide static user-defined SNMP OIDs
 oid 1.3.6.1.4.1.30155.42.3.1 name testStringValue read-only string "Test"
 oid 1.3.6.1.4.1.30155.42.3.4 name testIntValue read-write integer 1
+
+# Enable SNMPv3 USM with authentication, encryption and two defined users
+#seclevel enc
+#user "user1" authkey "password123" enc aes enckey "321drowssap"
+#user "user2" authkey "password456" enckey "654drowssap"