Fix compiling error when message doesn't have a move constructor. (#1678)

* Fix compiling error when message doesn't have a move constructor.

* Clear response safely.

Author: Barenboim

src/factory/RedisTaskImpl.cc

@@ -367,7 +367,7 @@ class ComplexRedisSubscribeTask : public ComplexRedisTask
 ProtocolMessage *
 ComplexRedisSubscribeTask::SubscribeWrapper::next_in(ProtocolMessage *message)
 {
-	redis_reply_t *reply = ((RedisResponse *)message)->result_ptr();
+	redis_reply_t *reply = task_->resp.result_ptr();
 
 	if (reply->type != REDIS_REPLY_TYPE_ARRAY)
 	{
@@ -385,7 +385,9 @@ ComplexRedisSubscribeTask::SubscribeWrapper::next_in(ProtocolMessage *message)
 	task_->watching_ = true;
 	task_->extract_(task_);
 
-	task_->clear_resp();
+	RedisResponse resp;
+	*(protocol::ProtocolMessage *)&resp = std::move(task_->resp);
+	task_->resp = std::move(resp);
 	return task_->finished_ ? NULL : &task_->resp;
 }
 

src/factory/WFTaskFactory.inl

@@ -179,9 +179,10 @@ protected:
 
 	void clear_resp()
 	{
-		RESP resp;
-		*(protocol::ProtocolMessage *)&resp = std::move(this->resp);
-		this->resp = std::move(resp);
+		protocol::ProtocolMessage head(std::move(this->resp));
+		this->resp.~RESP();
+		new(&this->resp) RESP;
+		*(protocol::ProtocolMessage *)&this->resp = std::move(head);
 	}
 
 	void disable_retry()