apibuild: Substitute only pure number tokens
apibuild: Substitute only pure number tokens

In 38df47c9af1 I've tried to prepare our apibuild.py script for
change made in 0628f3498ce (1U << 31). What I've done in the
former commit was to replace \d+U in parsed tokens with \d.
Problem was, my regular expression there was not quite right as
it also translated VIR_123U_VAL into VIR_123_VAL.

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

jfehlig/libvirt,jfehlig/libvirt,nertpinx/libvirt,crobinso/libvirt,jardasgit/libvirt,nertpinx/libvirt,zippy2/libvirt,datto/libvirt,fabianfreyer/libvirt,libvirt/libvirt,eskultety/libvirt,datto/libvirt,taget/libvirt,jardasgit/libvirt,libvirt/libvirt,fabianfreyer/libvirt,olafhering/libvirt,jardasgit/libvirt,nertpinx/libvirt,taget/libvirt,crobinso/libvirt,libvirt/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,zippy2/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,zippy2/libvirt,andreabolognani/libvirt,olafhering/libvirt,andreabolognani/libvirt,olafhering/libvirt,datto/libvirt,eskultety/libvirt,jfehlig/libvirt,libvirt/libvirt,eskultety/libvirt,eskultety/libvirt,eskultety/libvirt,taget/libvirt,crobinso/libvirt,taget/libvirt,fabianfreyer/libvirt,datto/libvirt,jardasgit/libvirt,datto/libvirt,olafhering/libvirt,taget/libvirt,jardasgit/libvirt,jfehlig/libvirt,zippy2/libvirt,crobinso/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,nertpinx/libvirt