Summary:
Add kill points in:
1. after creating a file
2. before writing a manifest record
3. before syncing manifest
4. before creating a new current file
5. after creating a new current file

Test Plan: Run all current tests.

Reviewers: yhchiang, igor, anthony, IslamAbdelRahman, rven, kradhakrishnan

Reviewed By: kradhakrishnan

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48855