CurrentUser: remove #as method.

Replace with CurrentUser#scoped.

app/logical/upload_service/controller_helper.rb

@@ -15,7 +15,7 @@ class UploadService
 
       if file
         # this gets called via XHR so we can process sync
-        Preprocessor.new(file: file).delayed_start(CurrentUser.id)
+        Preprocessor.new(file: file).delayed_start(CurrentUser.user)
       end
 
       [upload]

app/logical/upload_service/preprocessor.rb

@@ -54,8 +54,8 @@ class UploadService
       predecessor.present?
     end
 
-    def delayed_start(uploader_id)
-      CurrentUser.as(uploader_id) do
+    def delayed_start(uploader)
+      CurrentUser.scoped(uploader) do
         start!
       end
     rescue ActiveRecord::RecordNotUnique