static ip= address configuration does not end up in netplan file

static ip= address configuration does not end up in netplan file

klibc ipconfig process ip=...:$proto and dumps the state into a file, which is then parsed to generate runtime netplan configs.

For static ip configuration ipconfig parses $proto values "off" "none" "static" as the same PROTO_NONE and encodes it as PROTO="none" in the serialized state file.

The function that dumps ip data (_declare_ip_info()) has keys only values for dhcp dhcp4 dhcp6 static. But not "none" (used by ipconfig) or "off" (as valid by the kernel).

This means that netplan files generated in /run for static ip configuration are incomplete.

Imho we should accept "off" "none" "static" as all valid PROTO settings for static ip configuration.

[Impact]

 * `netplan apply` will not reapply static ip configuration as declared in ip= kernel cmdline.

[Test Case]

 * boot with static ip configuration in the kernel cmdline, e.g.

  ip=10.245.232.12::10.245.232.1:255.255.255.255:clound01:enc603:none

  Check that /run/netplan/*.yaml contains addresses stanzas.

[Regression Potential]

 * Runtime netplan configuration will now be more complete. Meaning that static ip addresses will now persist across `netplan apply` / downing, and reupping an interface. Whilst it was intended for static ip addresses to be there, it might be unexpected that they actually work properly now.