Fix problem with create_if_missing option when wal_dir is used

Summary: When wal_dir is used, DestroyDB is not passed the wal_dir option and so we get a Corruption exception.

Test Plan:
Verified manually that the following command line works now:
./db_bench --db=/mnt/db/rocksdb ... --disable_wal=0 --wal_dir=/data/users/rocksdb/WAL... --benchmarks=filluniquerandom --use_existing_db=0...

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29859
Update HISTORY.md for release 3.9
Fix calculation of max_total_wal_size in db_options_.max_total_wal_size == 0 case

Summary: This is a regression bug introduced by https://reviews.facebook.net/D24729 . max_total_wal_size would be off the target it should be more and more in the case that the a user holds the current super version after flush or compaction. This patch fixes it

Test Plan: make all check

Reviewers: yhchiang, rven, igor

Reviewed By: igor

Subscribers: ljin, yoshinorim, MarkCallaghan, hermanlee4, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29961
Fix #434

Summary: Why do we assert here? This doesn't seem like user friendly thing to do :)

Test Plan: none

Reviewers: sdong, yhchiang, rven

Reviewed By: rven

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D30027