Reorg of lib/3.6/packages.cf: document Redhat package_method bodies; introduce common_knowledge bundle and use it; overwrite all yum attributes with yum_rpm; use yum_rpm attributes in the generic package method.
update/update_bins.cf: add u_common_knowledge and use it.
Merge pull request #1 from tzz/feature/yum_rpm-and-common-knowledge

Reorg of lib/3.6/packages.cf for yum_rpm and common knowledge