Document udev rule

[jas4711]

Make sure the udev rule works everywhere and document how it is to be used. Compare ykpers.

[amluto]

For the Fedora package (still under review), I'm using:

KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="1050", ATTRS{idProduct}=="0113|0114|0115|0116|0120", ENV{ID_SECURITY_TOKEN}="1"

It would be nice to write a rule that detects the HID usage page 0xf1d0, but I'm not sure whether this can be done without a helper. I'll ping the udev people.

[amluto]

I'm trying to do this right:

http://lists.freedesktop.org/archives/systemd-devel/2014-October/024667.html

(NB: This supports non-Yubico devices, too, or at least it should. I haven't gotten my non-Yubico device to test with yet.)

[klali]

Good job with the systemd patch, very much the solution we hope for. Solving it in this library is just a band-aid.
I just backed out using ID_SECURITY_TOKEN though, didn't work for me (in 4a1ae95)

[nbraud]

This should likely be closed?