Recently (during Bluetooth UPF), a lot of developers experience
confusion due to weird errors in SMP, etc, which are actually irrelevant
and caused by the connection never having existed.
As a stop-gap measure, until upper layers properly report lower layer
failures, add a warning in the logs to stop wasting developer time.
Signed-off-by: Aleksander Wasaznik <aleksander.wasaznik@nordicsemi.no>
0d44528862