Fixes #7953: add product/repositories list for an erratum.

Display a list of products/repositories that an erratum is in.

http://projects.theforeman.org/issues/7953
I think this function needs to clear the content view param, I am seeing where if I have a content view selected and change environments I get no results because it is still sending a content_view_id that doesn't exist in this environment. Optionally, if the CV does exist for the changed to environment, keep that selection.