Ilya reported that the "which" utility is not that much portable and is
absent from Fedora. "type -p" is not portable either, and the correct
solution appears to be "command -v", so let's use this for now, we can
change it again in the future in case of problems.
Link: https://www.mail-archive.com/haproxy@formilux.org/msg36332.html
Some reg tests and their dependencies have been renamed. They may be
referenced by the .vtc files. So, this patch modifies also the references
to these dependencies.
