Summary:
A longstanding bug in our C interface can trigger this
assertion; see issue https://github.com/facebook/rocksdb/issues/6129. Disabling the assertion for now
(for 6.6.0) and will re-enable on fix of that bug.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6128

Differential Revision: D18854899

Pulled By: pdillinger

fbshipit-source-id: 9eb5294b9f11b208dc1a8cc148aaa31e47ff892b