[conformal/btcdb] 68d10f: Add some missing comments.

[John C. Vernaleo]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcdb
  Commit: 68d10f4dc8a75bc14b343758edb20258eb274c07
      
https://github.com/conformal/btcdb/commit/68d10f4dc8a75bc14b343758edb20258eb274c07
  Author: John C. Vernaleo <j...@conformal.com>
  Date:   2014-09-16 (Tue, 16 Sep 2014)

  Changed paths:
    M ldb/leveldb.go

  Log Message:
  -----------
  Add some missing comments.

ok @davecgh