log_checkpoints and restartpoint

Hi,

When log_checkpoints is enabled, checkpoint logs the number of
WAL files created/deleted/recycled, but restartpoint doesn't.
This is OK before 9.0 because restartpoint had never created/
deleted/recycled WAL files. But, in 9.0 or later, restartpoint might
do that while walreceiver is running. So I think that it's useful to
log those numbers even in restartpoint in the now.

The attached patch changes LogCheckpointEnd so that it logs
the number of WAL files created/deleted/recycled even in
restartpoint.

And I found the problem about the initialization of CheckpointStats
struct. The attached patch also fixes this.

Comments?

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center