[review] dcbw/nm-0-9-10-slaves

[Dan Williams <dcbw redhat com>]

Hi,

http://cgit.freedesktop.org/NetworkManager/NetworkManager/log/?h=dcbw/nm-0-9-10-slaves

Posting here since I'm too lazy to make a review bug.  This branch
backports some fixes to do the following things:

1) fully enable IP-less configs on interfaces
2) assume connections for slave interfaces
3) better cooperate with externally-managed interfaces
4) fix https://bugzilla.redhat.com/show_bug.cgi?id=1176319 (a crasher)

Review/testing appreciated.  This was the last issue before the release
of NM 0.9.10.2, which I considered a blocker because it causes a crash
in some not-so-rare circumstances.

Dan