Merge branch 'show-image-id-on-registry-page' into 'master'

Show proper image ID on registry page

## What does this MR do?
Display the container registry image ID (from the config blob) instead of the first image layer ID

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?
To show proper image ID on container_registry page.
This only supports manifest V2, since the manifest V1 doesn't expose information about Image ID.

## What are the relevant issue numbers?
Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/18159.

## Screenshots (if relevant)
![Screen_Shot_2016-06-21_at_13.16.44](/uploads/db0d3ed8c8b90fafc8dbf1644c2354b0/Screen_Shot_2016-06-21_at_13.16.44.png)

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] 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)

See merge request !4821

1 files changed, 2 insertions, 1 deletions

diff --git a/spec/features/container_registry_spec.rb b/spec/features/container_registry_spec.rb
index 53b4f027117..203e55a36f2 100644
--- a/spec/features/container_registry_spec.rb
+++ b/spec/features/container_registry_spec.rb
@@ -26,7 +26,8 @@ describe "Container Registry" do
     end
 
     context 'when there are tags' do
-      it { expect(page).to have_content(tag_name)}
+      it { expect(page).to have_content(tag_name) }
+      it { expect(page).to have_content('d7a513a66') }
     end
   end