Revert "[Rails5] Set request.format for artifacts_controller"

This reverts commit c48e7dc2.

# Conflicts:
#	app/controllers/projects/artifacts_controller.rb

app/controllers/projects/artifacts_controller.rb

@@ -9,7 +9,6 @@ class Projects::ArtifactsController < Projects::ApplicationController
   before_action :authorize_read_build!
   before_action :authorize_update_build!, only: [:keep]
   before_action :extract_ref_name_and_path
-  before_action :set_request_format, only: [:file]
   before_action :validate_artifacts!, except: [:download]
   before_action :entry, only: [:file]
 
@@ -110,12 +109,4 @@ class Projects::ArtifactsController < Projects::ApplicationController
 
     render_404 unless @entry.exists?
   end
-
-  def set_request_format
-    request.format = :html if set_request_format?
-  end
-
-  def set_request_format?
-    request.format != :json
-  end
 end