Bug#852596: iio-sensor-proxy still spams syslog with an error message every second

[Serhiy Cherpatyuk]

$ uname -a
Linux csy-aspire-v13 4.9.0-2-amd64 #1 SMP Debian 4.9.18-1 (2017-03-30) 
x86_64 GNU/Linux

syslog:
Apr 10 15:01:22 csy-aspire-v13 iio-sensor-prox[725]: Could not open 
input accel '/dev/input/event6': Operation not permitted