Enforce default column family options correctly

Summary:
There are several layers of column family options values. In order:

1) Defaults defined in ColumnFamilyOptions constructor
2) Defaults set explicitly in ha_rocksdb.cc code
3) Defaults set by rocksdb_default_cf_options sysvar
4) Per-CF options specified via rocksdb_cf_options_file

The settings from (2) were omitted inadvertently. This fixes it.

fbshipit-source-id: 2680d3a

storage/rocksdb/ha_rocksdb.cc

@@ -893,6 +893,7 @@ static bool rocksdb_show_status(handlerton*		hton,
 
 void get_cf_options(const std::string &cf_name, rocksdb::ColumnFamilyOptions *opts)
 {
+  *opts = default_cf_opts;
   rocksdb_cf_options_map.Get(cf_name, opts);
 }