Get vo-package-43.tar.gz from http://software-itb.grid.iu.edu/pacman/tarballs/, untar it.
Rename edg-mkgridmap.osg to edg-mkgridmap.conf
Get rid of gums.template and gums-fqan.txt
Copy gums.config.template from the previous vo-client package
Move vomsdir out of the way (if present)
Copy vomsdir from previous vo-client package.
Either:
    scp the whole directory to a fermicloud machine
    As root, run ./osg-make-vomsdir --vomsdir vomsdir --vomses vomses
Or:
    scp it to some machine you have grid credentials on
    Run grid-proxy-init
    Run ./osg-make-vomsdir --vomsdir vomsdir --vomses vomses

Merge vomsdir dir with the one you moved out of the way.
Get rid of the scripts and anything else that's not mentioned in the spec file.
Rename the directory vo-client-$version
Tar up the directory