Fix regress test to sleep after pgpool_reload

Fix regress test to sleep after pgpool_reload

Some regression tests test behaviors after pgpool-II configuration
is modified and reloaded. However, sometimes these modification
were not applied to pgpool just after reloading.

It was observed after the following commit.

 commit ba24a708ed61d6a5fa296451b194c4b448ed5966
 Author: Tatsuo Ishii <ishii@postgresql.org>
 Date:   Thu Aug 6 13:02:42 2015 +0900

 Issue fsync() when writing pgpool_status.

 This ensures that pgpool_status is saved to permanent storage and
 allow to survive after system crash.

It seem to be because fsync() takes a time before SIGHUP is sent
to child processes in reload_config().

Fix is to add sleep to wait for applying modification after
pgpool_reload.

In addition, some messages are added to test for debugging.