Remove dead code.
Remove dead code.

The dead code has been in the codebase since the initial commit and is
generating a compiler warning when used in Xcode.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=164174594

google/leveldb,dwing4g/leveldb,cmumford/leveldb,olzhabay/PMIndexDB,bitcoin-core/leveldb,likema/leveldb,fastogt/leveldb,bitcoin-core/leveldb,fuchsia-mirror/third_party-leveldb,olzhabay/PMIndexDB,likema/leveldb,bitcoin-core/leveldb,matehat/leveldb,fuchsia-mirror/third_party-leveldb,luke-jr/leveldb,matehat/leveldb,yuwolf/leveldb,yuwolf/leveldb,dwing4g/leveldb,yuwolf/leveldb,google/leveldb,luke-jr/leveldb,olzhabay/PMIndexDB,cmumford/leveldb,dwing4g/leveldb,fastogt/leveldb,matehat/leveldb