Add RPM spec file

SRPMs I built for EL6 are available here, http://yum.tamu.edu/zfsonlinux/epel/6/SRPMS/repoview/.  How I built them is here, https://github.com/treydock/rpmbuild-perl-Sun-Solaris-Kstat.  It would be nice to see them in the zfsonlinux repos at some point.