fixes #5030 - reload filter on package group/errata rule list

Since we are using the rule list on the filter object to determine which filter rule id to 
remove, we need to fetch the new list on each page load
re-iterating the same statement doesn't really help :)

I don't see anywhere where the rules are fetched directly.  They are iterated over from the filter itself here https://github.com/jlsherrill/katello/blob/filters/engines/bastion/app/assets/javascripts/bastion/content-views/details/filters/errata-filter-list.controller.js#L77

I can assure you it does not fetch any 'rules directly' in master.  You may be thinking of your PR?  I can re-test there and remove the errata fix here if it is fixed there.