The merge of lr/udev-unmanaged-fd731014 made all devices wait until
udev found them, but that makes these three device types fail activate
when created by NM itself.

Since their availability depended on IFF_UP, they could not be
activated (eg, 'nmcli con up team0') until they were IFF_UP.  But
when they are created by NM, although NM knows the ifindex the
platform ignores the interface until udev finds it.  Thus immediately
after creating the interface in _internal_activate_device() it
won't be known to the platform, so the nm_device_is_available()
check that controls whether the device moves to DISCONNECTED
will fail.  This prevents any activation and emits the message:

"Connection 'foo' is not available on the device %s at this time."

because the device is still in the UNAVAILABLE state.

danw asked why we care about IFF_UP for these devices, and I can't
remember why, and I don't think it makes sense to require now.