[Gluster-infra] Added new admin to maintainers mailinglist

[Niels de Vos]

Hi,

sankarshan at kadalu.io has been added to the admins/owners of the
maintainers list and he received login details off-list.

There were no admins listed anymore, not sure who deleted those since a
few weeks? list-admin at gluster.org has been added as well, it seems this
address is used for (all?) others lists too.

Niels