Since we enable MAC spoofing by default, users may experience network
connection issues on networks emplying MAC address blocking.
Unfortunately NetworkManager does not seem to offer any nice hook into
its error-handling, so when MAC spoofing is enabled we run (from T-G)
this crufty script which analyzes NM's log and tries to identify
connection failures that is unrelated to more common errors, like
entering an incorrect WPA passphrase. At the moment the script only
handles wifi networks, not wired, WAN, etc.