Change SYSFS to ATTRS

The SYSFS key has been [deprecated][1] on Nov 2009 and [removed][2] from udev on Oct 2010. The replacements are ATTR and ATTRS.

[1]: http://cgit.freedesktop.org/systemd/systemd/commit/?id=6d87ee2e0024074b77001e57ff1d7b7d24b1be68
[2]: http://cgit.freedesktop.org/systemd/systemd/commit/?id=289a1821a4a7636ce42a6c7adc3a9bb49421a5ea