add git-commit-title-method into pipeline model and modify view

add git-commit-title-method into tests

app/models/ci/pipeline.rb

@@ -51,6 +51,10 @@ module Ci
       commit.try(:message)
     end
 
+    def git_commit_title
+      commit.try(:title)
+    end
+
     def short_sha
       Ci::Pipeline.truncate_sha(sha)
     end

app/views/projects/builds/_sidebar.html.haml

@@ -96,7 +96,7 @@
     .title
       Commit title
     %p.build-light-text.append-bottom-0
-      #{@build.pipeline.commit.try(:title)}
+      #{@build.pipeline.git_commit_title}
 
   - if @build.tags.any?
     .block

spec/views/projects/builds/show.html.haml_spec.rb

@@ -22,6 +22,10 @@ describe 'projects/builds/show' do
     it 'does not show retry button' do
       expect(rendered).not_to have_link('Retry')
     end
+
+    it 'shows commit title' do
+      expect(rendered).to have_text(@git_commit_title)
+    end
   end
 
   context 'when build is not running' do
@@ -33,5 +37,10 @@ describe 'projects/builds/show' do
     it 'shows retry button' do
       expect(rendered).to have_link('Retry')
     end
+
+   it 'shows commit title' do
+      expect(rendered).to have_text(@git_commit_title)
     end
+  end
+
 end