Fix email option in config not parse correctly

Author: jackycute

lib/config.js

@@ -98,7 +98,7 @@ var google = (process.env.HMD_GOOGLE_CLIENTID && process.env.HMD_GOOGLE_CLIENTSE
     clientSecret: process.env.HMD_GOOGLE_CLIENTSECRET
 } : config.google || false;
 var imgur = process.env.HMD_IMGUR_CLIENTID || config.imgur || false;
-var email = process.env.HMD_EMAIL || config.email || false;
+var email = process.env.HMD_EMAIL ? (process.env.HMD_EMAIL === 'true') : !!config.email;
 
 function getserverurl() {
     var url = '';