Config option to turn AOF rewrite incremental fsync on/off.

src/redis.c

@@ -1200,6 +1200,7 @@ void initServerConfig() {
     server.aof_fd = -1;
     server.aof_selected_db = -1; /* Make sure the first time will not match */
     server.aof_flush_postponed_start = 0;
+    server.aof_rewrite_incremental_fsync = 1;
     server.pidfile = zstrdup("/var/run/redis.pid");
     server.rdb_filename = zstrdup("dump.rdb");
     server.aof_filename = zstrdup("appendonly.aof");