Retreive correct default iface dev name for raft members by default

[karbyshevds]

Currently deployment is failing in case if vault nodes have different default network interface name. E.x.:

• node1 have default network iface name ens160
• nodes node2 node3 have default network iface name wlp0s20f3

This PR makes default vault_raft_cluster_members work correctly when vault hosts have different device names.

[FalcoSuessgott]

please rebase against master and trigger CI again

[karbyshevds]

Rebased!

[FalcoSuessgott]

Thank you!