Remove redundant function declaration. (#1075)
Remove redundant function declaration. (#1075)

Makes clang happy again.
damonkohler/cartographer,larics/cartographer,wohe/cartographer,damonkohler/cartographer,googlecartographer/cartographer,larics/cartographer,cartographer-project/cartographer,wohe/cartographer,cartographer-project/cartographer,larics/cartographer,googlecartographer/cartographer,googlecartographer/cartographer,cartographer-project/cartographer,cartographer-project/cartographer,wohe/cartographer,larics/cartographer,googlecartographer/cartographer,damonkohler/cartographer,damonkohler/cartographer,wohe/cartographer