plugin: Remove plugin_request argument from callbacks

None of the existing callbacks was making use of it and we will be
exposing the method callback interface to outside compilation unit
where the struct definition is not visible. So just remove it.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

lightningd/plugin.c

@@ -71,8 +71,7 @@ struct plugin_request {
 	struct json_stream *stream;
 
 	/* The response handler to be called when plugin gives us an object. */
-	void (*cb)(const struct plugin_request *,
-		   const char *buffer,
+	void (*cb)(const char *buffer,
 		   const jsmntok_t *toks,
 		   const jsmntok_t *idtok,
 		   void *);
@@ -195,8 +194,7 @@ static void PRINTF_FMT(2,3) plugin_kill(struct plugin *plugin, char *fmt, ...)
  */
 static struct plugin_request *
 plugin_request_new_(struct plugin *plugin,
-		    void (*cb)(const struct plugin_request *,
-			       const char *buffer,
+		    void (*cb)(const char *buffer,
 			       const jsmntok_t *toks,
 			       const jsmntok_t *idtok,
 			       void *),
@@ -222,7 +220,6 @@ plugin_request_new_(struct plugin *plugin,
 	plugin_request_new_(					\
 	    (plugin),						\
 	    typesafe_cb_preargs(void, void *, (cb), (arg),	\
-				const struct plugin_request *,	\
 				const char *buffer,		\
 				const jsmntok_t *toks,		\
 				const jsmntok_t *idtok),	\
@@ -326,7 +323,7 @@ static void plugin_response_handle(struct plugin *plugin,
 	}
 
 	/* We expect the request->cb to copy if needed */
-	request->cb(request, plugin->buffer, toks, idtok, request->arg);
+	request->cb(plugin->buffer, toks, idtok, request->arg);
 
 	uintmap_del(&plugin->plugins->pending_requests, id);
 	tal_free(request);
@@ -633,8 +630,7 @@ static void json_stream_forward_change_id(struct json_stream *stream,
 		json_stream_append(stream, "\n");
 }
 
-static void plugin_rpcmethod_cb(const struct plugin_request *req,
-				const char *buffer,
+static void plugin_rpcmethod_cb(const char *buffer,
 				const jsmntok_t *toks,
 				const jsmntok_t *idtok,
 				struct command *cmd)
@@ -822,8 +818,7 @@ static void plugin_manifest_timeout(struct plugin *plugin)
 /**
  * Callback for the plugin_manifest request.
  */
-static void plugin_manifest_cb(const struct plugin_request *req,
-			       const char *buffer,
+static void plugin_manifest_cb(const char *buffer,
 			       const jsmntok_t *toks,
 			       const jsmntok_t *idtok,
 			       struct plugin *plugin)
@@ -1001,8 +996,7 @@ void plugins_init(struct plugins *plugins, const char *dev_plugin_debug)
 	}
 }
 
-static void plugin_config_cb(const struct plugin_request *req,
-			     const char *buffer,
+static void plugin_config_cb(const char *buffer,
 			     const jsmntok_t *toks,
 			     const jsmntok_t *idtok,
 			     struct plugin *plugin)