fix coverity scan problem

source/libs/stream/src/streamBackendRocksdb.c

@@ -705,7 +705,7 @@ int32_t streamStateOpenBackendCf(void* backend, char* name, char** cfs, int32_t
 
   rocksdb_options_t**              cfOpts = taosMemoryCalloc(nCf, sizeof(rocksdb_options_t*));
   RocksdbCfParam*                  params = taosMemoryCalloc(nCf, sizeof(RocksdbCfParam));
-  rocksdb_comparator_t**           pCompare = taosMemoryCalloc(nCf, sizeof(rocksdb_comparator_t**));
+  rocksdb_comparator_t**           pCompare = taosMemoryCalloc(nCf, sizeof(rocksdb_comparator_t*));
   rocksdb_column_family_handle_t** cfHandle = taosMemoryCalloc(nCf, sizeof(rocksdb_column_family_handle_t*));
 
   for (int i = 0; i < nCf; i++) {