[tex-live] lualatex fixes

[Karl Berry]

FYI, I've committed two small fixes from Elie (Roux) to the files
oberdiek.luatex.lua and pdftexcmds.lua in texmf-dist/scripts/oberdiek.
(Heiko is in the loop, and we all hope for a full oberdiek release soon.)

With these changes, at least I can load fontspec under current lualatex.
So hopefully some more realistic testing with that format can be done
now.

Thanks Elie.

karl