support multiple CFs with OPTIONS file

Summary:
Move an option necessary for running db_bench on multiple CFs into the general initialization area, so it works with both flag-based init and OPTIONS-based init.
Closes https://github.com/facebook/rocksdb/pull/2675

Differential Revision: D5541378

Pulled By: ajkr

fbshipit-source-id: 169926cb4ae95c17974f744faf7cc794d41e5c0a

tools/db_bench_tool.cc

@@ -2856,7 +2856,6 @@ void VerifyDBFromDB(std::string& truth_db_name) {
 
     assert(db_.db == nullptr);
 
-    options.create_missing_column_families = FLAGS_num_column_families > 1;
     options.max_open_files = FLAGS_open_files;
     if (FLAGS_cost_write_buffer_to_cache || FLAGS_db_write_buffer_size != 0) {
       options.write_buffer_manager.reset(
@@ -3203,6 +3202,7 @@ void VerifyDBFromDB(std::string& truth_db_name) {
   void InitializeOptionsGeneral(Options* opts) {
     Options& options = *opts;
 
+    options.create_missing_column_families = FLAGS_num_column_families > 1;
     options.statistics = dbstats;
     options.wal_dir = FLAGS_wal_dir;
     options.create_if_missing = !FLAGS_use_existing_db;