Fix parser for shadowsocks cipher none

infra/conf/shadowsocks.go

@@ -26,6 +26,8 @@ func cipherFromString(c string) shadowsocks.CipherType {
 		return shadowsocks.CipherType_AES_256_GCM
 	case "chacha20-poly1305", "aead_chacha20_poly1305", "chacha20-ietf-poly1305":
 		return shadowsocks.CipherType_CHACHA20_POLY1305
+	case "none", "plain":
+		return shadowsocks.CipherType_NONE
 	default:
 		return shadowsocks.CipherType_UNKNOWN
 	}