forgotten initalization of a variable

Hello.

The commit a7e8ece41c adds a new member restoreCommand to
XLogPageReadPrivate. readOneRecord doesn't make use of it but forgets
to set NULL. That can lead to illegal pointer access.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center
From 2260cf859ffa570639fd0b04cc94540a937e6042 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyoga.ntt@gmail.com>
Date: Tue, 21 Apr 2020 14:15:39 +0900
Subject: [PATCH] Properly initalize a variable.

Commit a7e8ece41c adds new member restoreCommand to
XLogPageReadPrivate, but forgot to initialize it with NULL in
readOneRecord. That leads to illegal pointer access in
SimpleXLogPageRead.
---
 src/bin/pg_rewind/parsexlog.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c
index 14a5db5433..542160c493 100644
--- a/src/bin/pg_rewind/parsexlog.c
+++ b/src/bin/pg_rewind/parsexlog.c
@@ -115,6 +115,7 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex)
     XLogRecPtr    endptr;
 
     private.tliIndex = tliIndex;
+    private.restoreCommand = NULL;
     xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead,
                                     &private);
     if (xlogreader == NULL)
-- 
2.18.2