Remove customized require behaviors and modify the bin executable
to check for missing tools that Vagrant expects to exist when
running outside of an installer.
- nfs.service got recently removed in openSUSE Tumbleweed and calling service
restart nfs errors out on Tumbleweed. nfs.service has been an alias to
nfs-client.target for a very long time and can thus be safely substituted.
- all actively supported versions of openSUSE & SLE are using systemd now
=> no reason not to use systemctl
