Fix leak on error.

src/persist_read_v234.c

@@ -179,6 +179,7 @@ int persist__chunk_base_msg_read_v234(FILE *db_fptr, struct P_base_msg *chunk, u
 
 	return MOSQ_ERR_SUCCESS;
 error:
+	mosquitto__FREE(chunk->payload);
 	mosquitto__FREE(chunk->source.id);
 	mosquitto__FREE(chunk->source.username);
 	mosquitto__FREE(chunk->topic);