Summary:
We should clean up after ourselves. Last crashtest failed because the disk on the cibuild machine was full.
Also, db_crashtest is supposed to run the test on the same database in every iteration. This isn't the case currently, because every run creates a new tmp directory. It's fixed with this diff.
Test Plan: ran it
Reviewers: ljin
Reviewed By: ljin
CC: leveldb
Differential Revision: https://reviews.facebook.net/D17073
4cfb0eb40f