Merge pull request #193 from lindig/UPD-825

CA-359978 UPD-825: Flush IP addresses when switching from static to DHCP

v0.56.1

- CP-3864: update for rpclib 7 compatibility
- CA-351826 ensure PIF is an ethernet device
- CA-351826 fail if we can't find MAC address of interface
- CA-351826 recognise link/infiniband MAC address