[oe] maintainers for wireshark/tshark, net-snmp, libpcap, tcpdump

[Sergey Lapin]

>> I have a set of patches implementing IEEE802.15.4 stuff, so these are
>> needed to be upgraded and patched.
>>
>> wireshark/tshark: buildability
>
> While you at at it,  could you please also bump the version of wshark/tshark
> to the upstream one?
'twas my initial intention, but it has some additional
cross-compile-unfriendly tests
which require some attention.