Fix leaking the xkb-state during keyboard destruction, leaking lots of xkb
references into the wild.
static void keyboard_free(idev_device *d) {
idev_keyboard *k = keyboard_from_device(d);
static void keyboard_free(idev_device *d) {
idev_keyboard *k = keyboard_from_device(d);
+ xkb_state_unref(k->xkb_state);
free(k->repdata.keyboard.codepoints);
free(k->repdata.keyboard.keysyms);
free(k->evdata.keyboard.codepoints);
free(k->repdata.keyboard.codepoints);
free(k->repdata.keyboard.keysyms);
free(k->evdata.keyboard.codepoints);