read_uevent() checks if the interface name is blacklisted, but then
continues to open the corresponding uevent file, and happily sets SERIVCE_TYPE
and DEVICE_TYPE (nullifying the blacklisting)

this leads to the following logging when starting connmand -I wlan0
  Ignoring interface wlan0 (filtered)
  Adding interface wlan0 [ wifi ]

fix this by bailing out from read_uevent() as soon as we find the device
is blacklisted