Add BuildArch of noarch to the redhat spec

When no BuildArch is present in the specfile, rpms will be built assuming the
build is arch specific. As razor is pure ruby, there is no compilation needed
and it should be a noarch package, so this commit adds a BuildArch of noarch to
the specfile.
Remove leading epoch from spec file changelog

This looks like a lingering artifact from the facter spec file. There was an
epoch of 1 in the spec file previously, and so the changelog had a leading 1 in
the version section. That wouldn't have affected the package but could be
confusing to those reading the changelog. This commit removes that epoch from
the changelog.
Merge pull request #394 from haus/specfile_fixups

Redhat spec file fixups