Fix compaction_job_test

Fix compaction_job_test

Summary:
Two issues:
* the input keys to the compaction don't include sequence number.
* sequence number is set to max(seq_num), but it should be set to max(seq_num)+1, because the condition here is strictly-larger (i.e. we will only zero-out sequence number if the DB's sequence number is strictly greater than the key's sequence number): https://github.com/facebook/rocksdb/blob/master/db/compaction_job.cc#L830

Test Plan: make compaction_job_test && ./compaction_job_test

Reviewers: sdong, lovro

Reviewed By: lovro

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D41247
(cherry picked from commit 155ce60dafbc3841da73eedf0d9dc6c4fabd8404)