SPARK-2662: Fix NPE for JsonProtocol

Author: GuoQiang Li <witgo@qq.com>

Closes #1511 from witgo/JsonProtocol and squashes the following commits:

2b6227f [GuoQiang Li] Fix NPE for JsonProtocol
[SPARK-2658][SQL] Add rule for true = 1.

Author: Michael Armbrust <michael@databricks.com>

Closes #1556 from marmbrus/fixBooleanEqualsOne and squashes the following commits:

ad8edd4 [Michael Armbrust] Add rule for true = 1 and false = 0.