Merge branch 'avoid-api-helper-call' into 'master'

Avoid helper call with default parameters

The helpers can ultimately be removed when the issue API uses the Grape DSL.

See merge request !7649

lib/api/merge_requests.rb

@@ -59,7 +59,7 @@ module API
           else merge_requests
           end
 
-        merge_requests = merge_requests.reorder(issuable_order_by => issuable_sort)
+        merge_requests = merge_requests.reorder(params[:order_by] => params[:sort])
         present paginate(merge_requests), with: Entities::MergeRequest, current_user: current_user, project: user_project
       end