Only tick queue if anything is updated

Feedback:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8664#note_22853522

app/services/ci/update_runner_service.rb

@@ -7,8 +7,8 @@ module Ci
     end
     def update(params)
-      runner.update(params).tap do
-        runner.tick_runner_queue
+      runner.update(params).tap do |updated|
+        runner.tick_runner_queue if updated
       end
     end
   end

spec/services/ci/update_runner_service_spec.rb

@@ -6,13 +6,36 @@ describe Ci::UpdateRunnerService, :services do
   describe '#update' do
     before do
       allow(runner).to receive(:tick_runner_queue)
-
-      described_class.new(runner).update(description: 'new runner')
     end
+    context 'with description params' do
+      let(:params) { { description: 'new runner' } }
+
       it 'updates the runner and ticking the queue' do
-      expect(runner.description).to eq('new runner')
+        expect(update).to be_truthy
+
+        runner.reload
+
         expect(runner).to have_received(:tick_runner_queue)
+        expect(runner.description).to eq('new runner')
+      end
+    end
+
+    context 'when params are not valid' do
+      let(:params) { { run_untagged: false } }
+
+      it 'does not update and give false because it is not valid' do
+        expect(update).to be_falsey
+
+        runner.reload
+
+        expect(runner).not_to have_received(:tick_runner_queue)
+        expect(runner.run_untagged).to be_truthy
+      end
+    end
+
+    def update
+      described_class.new(runner).update(params)
     end
   end
 end