Python 2 & 3 compatible code

[CrimsonGlory]

I have adapted the code so that it is compatible both with python 2.7 and python 3.
The code was tested with python versions 2.7.12, 2.7.17, 3.5.2 and 3.6.9 (just because those were the versions installed on the machines that I have with raid).

[genterminl]

I just tried this and get an error:

Traceback (most recent call last):
  File "/usr/local/src/lsdrv/lsdrv/./lsdrv-pr14", line 432, in <module>
    devstat = os.stat(mdev)
FileNotFoundError: [Errno 2] No such file or directory: '/dev/root'

The relevant line from /proc/mounts is "/dev/root / ext4 rw,noatime 0 0" and /dev/root does not expolicitly exist. I'm on Gentoo with kernel 6.14.5. I'm not really sure which utility or python call should be able to figure out the real device here (/dev/nvme0n1p2 in my case.)