Move is_link variable to the place it's used

We use the set_package before filter in many controllers
but use the is_link variable only one view. One less database
and one less backend query...

src/api/app/controllers/webui/packages/job_history_controller.rb

@@ -7,6 +7,7 @@ class JobHistoryController < Packages::MainController
       before_action :set_architecture
 
       def index
+        @is_link = @package.is_link? || @package.is_local_link?
         @jobshistory = @package.jobhistory(repository_name: @repository.name, arch_name: @architecture.name, package_name: @package_name, project_name: @project.name)
       end
     end

src/api/app/controllers/webui/packages/main_controller.rb

@@ -8,7 +8,6 @@ def set_package
         @package_name = params[:package_name]
         @package = ::Package.get_by_project_and_name(@project.to_param, params[:package_name],
                                                      use_source: false, follow_project_links: true, follow_multibuild: true)
-        @is_link = @package.is_link? || @package.is_local_link?
       rescue APIError
         raise ActiveRecord::RecordNotFound, 'Not Found'
       end