Fix Sidekiq ActiveJob integration setup

* .connect on a Redis connection wasn't valid
* Reset logger after we're done testing for redis connection to avoid
  "closed stream" error when starting server for real from a fork

activejob/test/support/integration/adapters/sidekiq.rb

@@ -48,7 +48,8 @@ def stop_workers
 
   def can_run?
     begin
-      Sidekiq.redis { |conn| conn.connect }
+      Sidekiq.redis { |conn| conn.info }
+      Sidekiq.logger = nil
     rescue
       return false
     end