[Feature?] Honour the networks set up by the network startup script

[Filip Miletic <filmil gmail com>]

A potentially useful feature for NetworkManager would be to read and
honour the network settings that are active prior to NM activation. This
would enable the user to set a 'fixed network' that is not touched by NM.

Namely, I've a couple of fixed network settings which get removed by NM
once it starts up. As a consequence, I must always configure the
interfaces manually when I connect to a network which does not support DHCP.

f