Use the rpm macro for configure, fix sysconfdir

* Use %configure instead of ./configure, which pre-populates prefix,
libdir, bindir, etc to Red Hat defaults
* Override sysconfdir to be %{_sysconfdir}/sysconfig so everything
looks in /etc/sysconfig/openafs/ for configuration files.
cacheinfo: Update file to use /var/cache/openafs instead of /usr/vice/cache