Fix Commit#status, feedback:

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6305#note_15230024

app/models/commit.rb

@@ -231,7 +231,7 @@ class Commit
   def status
     return @status if defined?(@status)
-    @status ||= pipelines.order(:id).last.try(:status)
+    @status ||= pipelines.status
   end
   def revert_branch_name

app/models/concerns/has_status.rb

@@ -20,7 +20,7 @@ module HasStatus
       skipped = scope.skipped.select('count(*)').to_sql
       deduce_status = "(CASE
-        WHEN (#{builds})=0 THEN NULL
+        WHEN (#{builds})=(#{created}) THEN NULL
         WHEN (#{builds})=(#{skipped}) THEN 'skipped'
         WHEN (#{builds})=(#{success})+(#{ignored})+(#{skipped}) THEN 'success'
         WHEN (#{builds})=(#{created})+(#{pending})+(#{skipped}) THEN 'pending'

spec/requests/api/commits_spec.rb

@@ -110,7 +110,7 @@ describe API::API, api: true  do
         get api("/projects/#{project.id}/repository/commits/#{project.repository.commit.id}", user)
         expect(response).to have_http_status(200)
-        expect(json_response['status']).to eq('created')
+        expect(json_response['status']).to be_nil
       end
     end