Revert "Rails5 fix format in uploads actions"

This reverts commit 4f76d953dd.

app/controllers/concerns/uploads_actions.rb

@@ -1,17 +1,11 @@
 # frozen_string_literal: true
 
 module UploadsActions
-  extend ActiveSupport::Concern
-
   include Gitlab::Utils::StrongMemoize
   include SendFileUpload
 
   UPLOAD_MOUNTS = %w(avatar attachment file logo header_logo favicon).freeze
 
-  included do
-    prepend_before_action :set_html_format, only: :show
-  end
-
   def create
     link_to_file = UploadService.new(model, params[:file], uploader_class).execute
 
@@ -61,13 +55,6 @@ module UploadsActions
 
   private
 
-  # Explicitly set the format.
-  # Otherwise rails 5 will set it from a file extension.
-  # See https://github.com/rails/rails/commit/84e8accd6fb83031e4c27e44925d7596655285f7#diff-2b8f2fbb113b55ca8e16001c393da8f1
-  def set_html_format
-    request.format = :html
-  end
-
   def uploader_class
     raise NotImplementedError
   end