修正HTTP解析层处理HTTP-Header的错误流程

* 原流程在解析同一个Field-Value对时，无法正确处理Header多次调用拼成完整字符串的情况，现修正；
* 原流程在处理Field-Value底层Buffer时计算长度有误，导致清空buffer时剩余最后的'\0'，现修正。

plugin/protocol/http/include/internal/http_half.h

@@ -51,8 +51,12 @@ struct http_half_private
 	short minor;
 
 	struct evbuffer * evbuf_uri;
+
 	struct evbuffer * evbuf_header_field;
 	struct evbuffer * evbuf_header_value;
+	bool is_evbuf_header_field_set;
+	bool is_evbuf_header_value_set;
+
 	struct evbuffer * evbuf_body;
 
 	enum hf_private_status body_status;
@@ -64,6 +68,7 @@ struct http_half_private
 };
 
 struct http_half_private * hf_private_create(tfe_http_direction ht_dir, short major, short minor);
+
 void hf_private_destory(struct http_half_private * hf_private);
 
 /** Parse the raw tcp input for HTTP half structure
@@ -83,5 +88,7 @@ int hf_private_parse(struct http_half_private * hf_private, const unsigned char
 void hf_private_set_callback(struct http_half_private * hf_private, hf_private_cb * cb,
 	void * user, void (* fn_user_deleter)(void *));
 
+void hf_private_set_session(struct http_half_private * hf_private, struct http_session_private * hs_private);
+
 struct http_session_private * hs_private_create(struct http_connection_private * hc_private,
 	struct http_half_private * hf_private_req, struct http_half_private * hf_private_resp);