[SNMP4J] Trap Agent Address & IPv6

[Senthil Muniswamy]

Frank,

In the Proxy Agent, when a SNMPv2 trap from IPv6 agent gets translated as
SNMPv1 trap, the IpAddress is created with Inet6Address
[PDUv1.setAgentAddress(org.snmp4j.smi.IpAddress agentAddress)].

It causes java.nio.BufferOverflowException during BER encoding because
org.snmp4j.smi.IpAddress can not handle IPv6 address.

Additional checking is required to set only IPv4 where ever agent address is
set.

-Senthil