replay_location indicates incorrect location

Hi,

When I looked at pg_stat_replication just after starting the standby before
executing any write transactions on the master, I found that replay_location
indicated incorrect location different from sent/write/flush_location. Then,
if I ran write transaction on the master, replay_location indicated the same
location as the others.

The cause of this problem is that Xlogctl->recoveryLastRecPtr which points
to replay_location is initialized with wrong variable ReadRecPtr. Instead, it
should be initialized with EndRecPtr. Attached patch does that. This needs
to be backported to 9.0.

Regards,

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