`DefaultGeoOperations.radius(…)` throws `NullPointerException` in pipeline mode

[yarooh]

In LettuceConnection pipeline mode, using DefaultGeoOperations to call geo-related methods will get null, then convert the return value by calling method deserializeGeoResults will throw NPE.
To avoid NPE,check if the source is null before deserializeGeoResults conversion.

[yarooh]

For example：
redisTemplate.executePipelined(new SessionCallback<Void>() { @Override public Void execute(RedisOperations operations) throws DataAccessException { operations.opsForGeo().radius(key, within); return null; } });
it will fail and throw npe。
Must use RedisCallback because it doesn't do deserializeGeoResults
List<Object> geoInfos = redisTemplate.executePipeline((RedisCallback<Void>) connection -> { connection.geoCommands().geoRadius(key, within); return null; });