Prefer rr.report over rr.report_results in SavedReportPaging mixin

https://bugzilla.redhat.com/show_bug.cgi?id=1590908

This not only makes it so we are consistent between the main controller
and the mixin, but this is also much faster to use this over
`MiqReportResult#report_results` when there is a large `binary_blob`
associated with the `MiqReportResult` record.

app/controllers/mixins/saved_report_paging.rb

@@ -14,7 +14,7 @@ def saved_report_paging
       @sb[:pages][:perpage] = settings(:perpage, :reports)
 
       rr = MiqReportResult.find(@sb[:pages][:rr_id])
-      @html = report_build_html_table(rr.report_results,
+      @html = report_build_html_table(rr.report,
                                       rr.html_rows(:page     => @sb[:pages][:current],
                                                    :per_page => @sb[:pages][:perpage]).join)