fix: use random string when failing to get MAC address for signature

We use a local MAC address to randomise sha1 to sign the message. In case MAC address is unreadable (CI env, for example), we defaulted to a random number, causing a crash in crypto.

Using `Math.random` is probably as random as `uuid`, but `crypto.createHash('sha1').update(mac)` requires a Buffer or a String, and not a number.

lib/analytics.js

@@ -12,6 +12,7 @@ var os = require('os');
 var osName = require('os-name');
 var interfaces = os.networkInterfaces() || os.getNetworkInterfaces();
 var crypto = require('crypto');
+var uuid = require('uuid');
 
 var metadata = {};
 
@@ -48,7 +49,7 @@ function postAnalytics(data) {
     data.os = osName(os.platform(), os.release());
     data.nodeVersion = process.version;
 
-    var mac = getMAC() || Math.random(); // ¯\_(ツ)_/¯
+    var mac = getMAC() || uuid.v4();
     var shasum = crypto.createHash('sha1');
     data.id = shasum.update(mac).digest('hex');