[Xcb] A fix for xkb and two for xinput

[Daniel Martin]

Hi folks,

I've found those 3 defects. Those defects don't look like being in a
critical or important path to me, especially the xinput stuff. Though,
something we should fix.

I didn't found them by reviewing, but with Python and magical alignment
tests. ;) But, nothing worth to announce yet.


Cheers,
    Daniel Martin