Actor: fix broken callback in pool

Author: pitr-ch

lib/concurrent/actor/utils/pool.rb

@@ -45,9 +45,7 @@ def on_message(message)
                                  else
                                    Envelope.new(envelope.message, Concurrent.future, envelope.sender, envelope.address)
                                  end
-          envelope_to_redirect.future.on_completion!(&lambda do |balancer, success, value, reason|
-                                                       balancer << :subscribe
-                                                     end.curry[@balancer])
+          envelope_to_redirect.future.on_completion! { @balancer << :subscribe } # TODO check safety of @balancer reading
           redirect @balancer, envelope_to_redirect
         end
       end

spec/concurrent/actor_spec.rb

@@ -324,7 +324,7 @@ def on_message(message)
             end
           end
 
-          expect(pool.ask!(5)).to eq 10
+          10.times { expect(pool.ask!(5)).to eq 10 }
           expect(pool.ask(:fail).reason).to be_kind_of RuntimeError
           expect(pool.ask!(5)).to eq 10
           terminate_actors pool