Refactor pipline info box view

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/views/projects/pipelines/_info.html.haml

-- commit = local_assigns.fetch(:commit)
-
-- return unless commit&.present?
-
 .commit-box
   %h3.commit-title
     = markdown(commit.title, pipeline: :single_line)

app/views/projects/pipelines/show.html.haml

@@ -4,9 +4,9 @@
 - page_title "Pipeline"
 
 .js-pipeline-container{ class: container_class, data: { controller_action: "#{controller.action_name}" } }
-
   #js-pipeline-header-vue.pipeline-header-container
 
+  - if @pipeline.commit.present?
     = render "projects/pipelines/info", commit: @pipeline.commit
 
   = render "projects/pipelines/with_tabs", pipeline: @pipeline