I have the same problem
Looks like in Openhabian I2C support was striped
I2C module is running, checked with this command
[19:14:44] openhabian@openHABianPi:~$ lsmod | grep i2c_
i2c_dev 6788 0
i2c_bcm2708 5930 0
[19:14:44] openhabian@openHABianPi:~$ sudo i2cdetect -y 1
Error: Could not open file `/dev/i2c-1' or `/dev/i2c/1': No such file or directory