Do things in the correct order

app/models/ci/runner.rb

@@ -132,6 +132,7 @@ module Ci
 
     def ensure_runner_queue_value
       Gitlab::Redis.with do |redis|
+        value = Time.new.inspect
         redis.set(runner_queue_key, value, ex: 60.minutes, nx: true)
         redis.get(runner_queue_key)
       end

lib/ci/api/builds.rb

@@ -21,6 +21,8 @@ module Ci
             return build_not_found!
           end
 
+          new_update = current_runner.ensure_runner_queue_value
+
           build = Ci::RegisterBuildService.new.execute(current_runner)
 
           if build
@@ -31,7 +33,6 @@ module Ci
           else
             Gitlab::Metrics.add_event(:build_not_found)
 
-            new_update = current_runner.ensure_runner_queue_value
             headers 'X-GitLab-Last-Update', new_update
 
             build_not_found!