Created logout method

Author: joaobentes

lib/zabbix.js

@@ -106,5 +106,13 @@ Client.prototype.login = function login(callback) {
   );
 };
 
+//Version 2.4 uses the method user.logout
+Client.prototype.logout = function login(callback) {
+  this.rpcid = 0; // Reset this, why not?
+  this.call('user.logout', {}, function (error, response, body) {
+      callback(error, response, body);
+    }.bind(this)
+  );
+};
 
 module.exports = Client;