Fixed; allow for falsy values as the configuration value of `log leve…

…l` (fixes #491).

lib/manager.js

@@ -141,7 +141,7 @@ Manager.prototype.__defineGetter__('log', function () {
   if (this.disabled('log')) return;
 
   var logger = this.get('logger');
-  logger.level = this.get('log level');
+  logger.level = this.get('log level') || -1;
 
   return logger;
 });