add a new package method to support package without architecture and ver...

...sion

This is an additional package promise to support the use case where the package name supplied in the policy might be identical to the prefix of other packages and a version and architecture string are not supplied. e.g. perl might be the package name in the promise, but there are many packages prefixed with perl-. yum_rpm regexp expands to <name>-.* when no architecture and version are supplied. This causes all packages prefixed with perl- to be installed. This proposed additional package method works around that problem by using $(name) as the package_name_convention