pgsql: Fix bogus time printout in walreceiver's debug log messages.

Fix bogus time printout in walreceiver's debug log messages.

The displayed sendtime and receipttime were always exactly equal, because
somebody forgot that timestamptz_to_str returns a static buffer (thereby
simplifying life for most callers, at the cost of complicating it for those
who need two results concurrently). Apply the same pstrdup solution used
by the other call sites with this issue. Back-patch to 9.2 where the
faulty code was introduced. Per bug #9849 from Haruka Takatsuka, though
this is not exactly his patch.

Possibly we should change timestamptz_to_str's API, but I wouldn't want
to do so in the back branches.

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/ed1cb4241585efe86d45edfed9eaf1995aa5421f

Modified Files
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src/backend/replication/walreceiver.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)