[JNI] Add JNI bindings for rocksdb Options

Added JNI bindings for following options:

block_size
max_write_buffer_number
write_buffer_size
disable_seek_compaction
max_background_compactions

Test Plan: make sample

Reviewers: haobo, dhruba, yhchiang

Reviewed By: yhchiang

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17523