Fix entry lookup in CI config inheritance rules

lib/gitlab/ci/config/entry/job.rb

@@ -108,7 +108,7 @@ module Gitlab
 
             self.class.nodes.each_key do |key|
               global_entry = deps[key]
-              job_entry = @entries[key]
+              job_entry = self[key]
 
               if global_entry.specified? && !job_entry.specified?
                 @entries[key] = global_entry

spec/lib/gitlab/ci/config/entry/global_spec.rb

@@ -254,7 +254,9 @@ describe Gitlab::Ci::Config::Entry::Global do
     end
 
     context 'when job does not have commands' do
-      let(:hash) { { rspec: { stage: 'test' } } }
+      let(:hash) do
+        { before_script: ['echo 123'], rspec: { stage: 'test' } }
+      end
 
       describe '#errors' do
         it 'reports errors about missing script' do