Link to the tag from a version instead of commit

This will result in a 404 when running an unreleased security patch
while still allowing users to find the commit when it is made available.

app/views/help/index.html.haml

@@ -7,8 +7,7 @@
   GitLab
   Enterprise Edition
   - if user_signed_in?
-    %span= Gitlab::VERSION
-    %small= link_to Gitlab.revision, Gitlab::COM_URL + namespace_project_commits_path('gitlab-org', 'gitlab-ee', Gitlab.revision)
+    %span= link_to Gitlab::VERSION, Gitlab::COM_URL + namespace_project_tag_path('gitlab-org', 'gitlab-ee', "v#{Gitlab::VERSION}")
     = version_status_badge
   %hr
 

spec/views/help/index.html.haml_spec.rb

@@ -21,7 +21,7 @@ describe 'help/index' do
       render
 
       expect(rendered).to match '8.0.2'
-      expect(rendered).to have_link('abcdefg', href: 'https://gitlab.com/gitlab-org/gitlab-ee/commits/abcdefg')
+      expect(rendered).to have_link('8.0.2', href: 'https://gitlab.com/gitlab-org/gitlab-ee/tags/v8.0.2')
     end
   end