Restoring NetworkManager settings

[Alan Evans]

I screwed up.

I wanted to temporarily assign static IP settings for eth0, and like a
dufus I used system-config-network. Unchecked "Controlled by Network
Manager" and entered the desired addresses. This worked fine as far as
it went.

When I was finished with the temporary settings, I went back and
re-checked the box for NetworkManager control. But NM never really
"took control" of eth0 again. I looked in "Edit Connections..." from
NM and saw that what used to be "Auto eth0" now said "System eth0."
There was no obvious way to change or delete it. Even root wasn't
allowed to delete it from the NM dialog.

I eventually did manage to get "Auto eth0" back by manually deleting
/etc/sysconfig/network-scripts/ifcfg-eth0. But I can't edit anything
about the connection, which is what I should have done instead of
involving system-config-network.  Everything under the edit dialog for
Auto eth0 is grayed out.

I booted the LiveCD just to confirm that it was not always so. Sure
enough, from the LiveCD boot, I can freely edit eth0 using
NetworkManager. How do I get that back?

-Alan