pgsql: pg_dump: Set private_date pointer to NULL in callback

pg_dump: Set private_date pointer to NULL in callback

The end callback for ZStandard compression frees the private_data
but didn't set the pointer to NULL after freeing.  This is not a
bug as the code is right now, since nothing is dereferencing the
pointer upon returning from the callback but it is good practice
to do.

Author: Alexander Kuznetsov <kuznetsovam@altlinux.org>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/efaee52b-9550-44ca-8633-ea86076b3283@altlinux.org

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/b669293e3432ee8fdcd44854a945837bb18eea5c

Modified Files
--------------
src/bin/pg_dump/compress_zstd.c | 1 +
1 file changed, 1 insertion(+)