[Rocksdb] fix wrong assert

Summary: the assert was wrong in D11145. Broke build

Test Plan: make db_bench run it

Reviewers: dhruba, haobo, emayanke

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D11187

include/leveldb/statistics.h

@@ -189,8 +189,8 @@ std::shared_ptr<Statistics> CreateDBStatistics();
 inline void RecordTick(std::shared_ptr<Statistics> statistics,
                        Tickers ticker,
                        uint64_t count = 1) {
-  assert(HistogramsNameMap.size() == HISTOGRAM_ENUM_MAX - 1);
-  assert(TickersNameMap.size() == TICKER_ENUM_MAX -1);
+  assert(HistogramsNameMap.size() == HISTOGRAM_ENUM_MAX);
+  assert(TickersNameMap.size() == TICKER_ENUM_MAX);
   if (statistics) {
     statistics->recordTick(ticker, count);
   }