At startup the manager tries to create virtual devices without a
specific order and spits warnings when a device can't be realized
because the parent device is not yet created. These failures are not
something the user should worry about because the creation will be
retried when the parent appears.
A better approach is to return an error code from the device's
create_and_realize() telling that it failed because the parent doesn't
exist. In this way, the manager knows that the device isn't ready and
can avoid printing warning messages.
Previously when the interface created by pppd was already the one we
expected, we would rename it to itself and remove the device from the
manager. Don't do it.
Fixes: 6c3195931e
Add code to NMPppDevice to activate new-style PPPoE connections. This
is a bit tricky because we can't create the link as usual in
create_and_realize(). Instead, we create a device without ifindex and
start pppd in stage2; when pppd reports a new configuration, we rename
the platform link to the correct name and set the ifindex into the
device.
This mechanism is inherently racy, but there is no way to tell pppd to
create an arbitrary interface name.
The new device type represents a PPP interface, and will implement the
activation of new-style PPPoE connections, i.e. the ones that don't
claim the parent device.
