pg_basebackup: Add missing PQclear in error path

This adds a missing PQclear in the error path of StreamLogicalLog, a
fix in the same vein as e889422d98 with an equivalent low impact.

Author: Steven Niu <niushiji@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/c4b1c627-a3e4-4347-a670-1e28a43ce0eb@gmail.com

src/bin/pg_basebackup/pg_recvlogical.c

@@ -633,6 +633,7 @@ StreamLogicalLog(void)
 	{
 		pg_log_error("unexpected termination of replication stream: %s",
 					 PQresultErrorMessage(res));
+		PQclear(res);
 		goto error;
 	}
 	PQclear(res);