[CBO] Warning FIX (#6420)

Author: pashandor789

ydb/core/kqp/opt/kqp_opt.h

@@ -24,8 +24,8 @@ struct TKqpOptimizeContext : public TSimpleRefCount<TKqpOptimizeContext> {
     const NYql::TKikimrConfiguration::TPtr Config;
     const TIntrusivePtr<NYql::TKikimrQueryContext> QueryCtx;
     const TIntrusivePtr<NYql::TKikimrTablesData> Tables;
-    int JoinsCount;
-    int EquiJoinsCount;
+    int JoinsCount{};
+    int EquiJoinsCount{};
 
     bool IsDataQuery() const {
         return QueryCtx->Type == NYql::EKikimrQueryType::Dml;