Add upstream patches that went into RHEL
- device: don't change MTU unless explicitly configured (rh #1460760)
- core: don't remove external IPv4 addresses (rh #1459813)
- cli: fix output of iface in overview output (rh#1460219)
- ppp: unexport NMPPPManager instance on dispose (rh#1459579)
- cli: remove spurious device names from wifi subcommands output (rh#1460527)