Merge branch '19420-render-only-commit-title' into 'master'

Render only commit title

## What does this MR do?
Render only commit title in builds



## Why was this MR needed?
Better readability

## What are the relevant issue numbers?
Closes #19420 

## Screenshots (if relevant)
![after](/uploads/fcdd59d74a0f91f6ac847f7f02d5f07f/after.png)![before](/uploads/71ca6dabf31452a1a8dfb15ecb8860c5/before.png)
## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added


- Tests

- [x] All builds are passing
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

cc: @kradydal @yorickpeterse @grzesiek @tmaczukin @dzaporozhets [@tomash](https://github.com/tomash) [@chastell](https://github.com/chastell)

this is connected to closed MR [!5109](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5109)

See merge request !5131

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

@@ -94,9 +94,9 @@
 
   .block
     .title
-      Commit message
+      Commit title
     %p.build-light-text.append-bottom-0
-      #{@build.pipeline.git_commit_message}
+      #{@build.pipeline.git_commit_title}
 
   - if @build.tags.any?
     .block

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

@@ -3,8 +3,12 @@ require 'spec_helper'
 describe 'projects/builds/show' do
   include Devise::TestHelpers
 
-  let(:build) { create(:ci_build) }
-  let(:project) { build.project }
+  let(:project) { create(:project) }
+  let(:pipeline) do
+    create(:ci_pipeline, project: project,
+                         sha: project.commit.id)
+  end
+  let(:build) { create(:ci_build, pipeline: pipeline) }
 
   before do
     assign(:build, build)
@@ -34,4 +38,15 @@ describe 'projects/builds/show' do
       expect(rendered).to have_link('Retry')
     end
   end
+
+  describe 'commit title in sidebar' do
+    let(:commit_title) { project.commit.title }
+
+    it 'shows commit title and not show commit message' do
+      render
+      
+      expect(rendered).to have_css('p.build-light-text.append-bottom-0',
+        text: /\A\n#{Regexp.escape(commit_title)}\n\Z/)
+    end
+  end
 end