Use Project `:repository` trait where necessary in migration specs

spec/migrations/migrate_process_commit_worker_jobs_spec.rb

@@ -4,7 +4,7 @@ require 'spec_helper'
 require Rails.root.join('db', 'migrate', '20161124141322_migrate_process_commit_worker_jobs.rb')
 
 describe MigrateProcessCommitWorkerJobs do
-  let(:project) { create(:project) }
+  let(:project) { create(:project, :repository) }
   let(:user) { create(:user) }
   let(:commit) { project.commit.raw.raw_commit }