Getting colder with our second freeze... it's 3.31.91 release day and string freeze, upload a tarball and lock those strings
The Wacom Xorg driver assigns a serial number of 1 for any pad that doesn't have a serial. libinput assigns 0. Just treat 1 as 0 here, there are no pens with a real serial 1 anyway.
Fixes #414 (closed)