[PATHC] Fix minor memory leak in pg_basebackup

Hi all

In some cases , PGresult is not cleared.

File: src\bin\pg_basebackup\streamutil.c

bool
RetrieveWalSegSize(PGconn *conn)
{
PGresult *res;
......
res = PQexec(conn, "SHOW wal_segment_size");
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
pg_log_error("could not send replication command \"%s\": %s",
"SHOW wal_segment_size", PQerrorMessage(conn));

PQclear(res); // *** res is cleared ***
return false;
}
......
/* fetch xlog value and unit from the result */
if (sscanf(PQgetvalue(res, 0, 0), "%d%s", &xlog_val, xlog_unit) != 2)
{
pg_log_error("WAL segment size could not be parsed");
return false; // *** res is not cleared ***
}
......
if (!IsValidWalSegSize(WalSegSz))
{
pg_log_error(ngettext("WAL segment size must be a power of two between 1 MB and 1 GB, but the remote server reported a value of %d byte",
"WAL segment size must be a power of two between 1 MB and 1 GB, but the remote server reported a value of %d bytes",
WalSegSz),
WalSegSz);
return false; ; // *** res is not cleared ***
}
......

Here is a patch.

Best Regards!