Do not assume file attribute

But instead, ask the replicator to ask the CarrierWaveUploader to tell
what the path of the file is.

ee/lib/gitlab/geo/replicable_model.rb

@@ -84,9 +84,9 @@ module Gitlab
       # @return [Boolean] whether the file exists on storage
       def file_exist?
         if local?
-          File.exist?(file.path)
+          File.exist?(replicator.carrierwave_uploader.path)
         else
-          file.exists?
+          replicator.carrierwave_uploader.exists?
         end
       end
     end