use global 'timeout' option for forwarding queries (#1284)

* Update plugins.go

* Update plugin_forward.go

dnscrypt-proxy/plugin_forward.go

@@ -93,7 +93,7 @@ func (plugin *PluginForward) Eval(pluginsState *PluginsState, msg *dns.Msg) erro
 	}
 	server := servers[rand.Intn(len(servers))]
 	pluginsState.serverName = server
-	client := dns.Client{Net: pluginsState.serverProto}
+	client := dns.Client{Net: pluginsState.serverProto, Timeout: pluginsState.timeout}
 	respMsg, _, err := client.Exchange(msg, server)
 	if err != nil {
 		return err

dnscrypt-proxy/plugins.go

@@ -87,6 +87,7 @@ type PluginsState struct {
 	returnCode                       PluginsReturnCode
 	serverName                       string
 	serverProto                      string
+	timeout                          time.Duration
 }
 
 func (proxy *Proxy) InitPluginsGlobals() error {
@@ -240,6 +241,7 @@ func NewPluginsState(proxy *Proxy, clientProto string, clientAddr *net.Addr, ser
 		qName:                            "",
 		serverName:                       "-",
 		serverProto:                      serverProto,
+		timeout:                          proxy.timeout,
 		requestStart:                     start,
 		maxUnencryptedUDPSafePayloadSize: MaxDNSUDPSafePacketSize,
 		sessionData:                      make(map[string]interface{}),