content views: undefined method error while publish a CV that includes errata filter
fixes #4915 - content view publish - resolve method undefined errors
This commit addresses a couple of undefined method errors that
have been observed.
- package_clause_generator - observed error in production configuration
when filter contained errata; however, same should occur for package
- content_view_erratum_filter - observed error if the errata id filter
was empty (ie. no rules/ids)