Fix RuboCop offenses for duplicated methods

app/controllers/projects/issues_controller.rb

@@ -191,10 +191,6 @@ class Projects::IssuesController < Projects::ApplicationController
     return render_404 unless can?(current_user, :read_issue, @issue)
   end
 
-  def authorize_read_issue!
-    return render_404 unless can?(current_user, :read_issue, @issue)
-  end
-
   def authorize_update_issue!
     return render_404 unless can?(current_user, :update_issue, @issue)
   end

app/models/project.rb

@@ -607,11 +607,6 @@ class Project < ActiveRecord::Base
     RepositoryUpdateMirrorWorker.perform_in(delay, self.id)
   end
 
-  def mark_import_as_failed(error_message)
-    import_fail
-    update_column(:import_error, Gitlab::UrlSanitizer.sanitize(error_message))
-  end
-
   def has_remote_mirror?
     remote_mirrors.enabled.exists?
   end