Summary:
`scratch` is not initialized in `Align` because it will be set outside of it. But clang analyzer is strict on initializing it before return.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6577
Test Plan: make analyze
Reviewed By: siying
Differential Revision: D20607303
Pulled By: cheng-chang
fbshipit-source-id: 2843d759345a057a8e122178d30b90deff0f9b2a