[SPARK-5002][SQL] Using ascending by default when not specify order in order by

spark sql does not support ```SELECT a, b FROM testData2 ORDER BY a desc, b```.

Author: wangfei <wangfei1@huawei.com>

Closes #3838 from scwf/orderby and squashes the following commits:

114b64a [wangfei] remove nouse methods
48145d3 [wangfei] fix order, using asc by default
[Spark-4512] [SQL] Unresolved Attribute Exception in Sort By

It will cause exception while do query like:
SELECT key+key FROM src sort by value;

Author: Cheng Hao <hao.cheng@intel.com>

Closes #3386 from chenghao-intel/sort and squashes the following commits:

38c78cc [Cheng Hao] revert the SortPartition in SparkStrategies
7e9dd15 [Cheng Hao] update the typo
fcd1d64 [Cheng Hao] rebase the latest master and update the SortBy unit test