Summary:
* [java] Add a java api for rocksdb::Options, currently only supports create_if_missing.
* [java] Add a test for RocksDBException in RocksDBSample.
Test Plan: make jtest
Reviewers: haobo, sdong
Reviewed By: haobo
CC: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D17385
