fix: two segmentation faults in cluster::guild_edit_member and cluster::tick_timers/cluster::shutdown (#1326)

Author: KTuff

src/dpp/cluster.cpp

@@ -319,6 +319,7 @@ void cluster::shutdown() {
 		delete t.second;
 	}
 	timer_list.clear();
+	next_timer.clear();
 	/* Terminate shards */
 	for (const auto& sh : shards) {
 		log(ll_info, "Terminating shard id " + std::to_string(sh.second->shard_id));

src/dpp/cluster/guild_member.cpp

@@ -30,7 +30,7 @@ void cluster::guild_add_member(const guild_member& gm, const std::string &access
 
 
 void cluster::guild_edit_member(const guild_member& gm, command_completion_event_t callback) {
-	this->post_rest(API_PATH "/guilds", std::to_string(gm.guild_id), "members/" + std::to_string(gm.user_id), m_patch, gm.build_json(), [this, &gm, callback](json &j, const http_request_completion_t& http) {
+	this->post_rest(API_PATH "/guilds", std::to_string(gm.guild_id), "members/" + std::to_string(gm.user_id), m_patch, gm.build_json(), [this, gm, callback](json &j, const http_request_completion_t& http) {
 		if (callback) {
 			callback(confirmation_callback_t(this, guild_member().fill_from_json(&j, gm.guild_id, gm.user_id), http));
 		}