configfile: check if logger available first

else:
````
/usr/local/haraka.matt/configfile.js:324
            throw err;
                  ^
TypeError: Cannot call method 'logdebug' of undefined
    at /usr/local/haraka.matt/configfile.js:300:28
    at Array.forEach (native)
    at Object.cfreader.load_ini_config (/usr/local/haraka.matt/configfile.js:274:15)
    at Object.cfreader.load_config (/usr/local/haraka.matt/configfile.js:180:27)
    at Object.cfreader.read_config (/usr/local/haraka.matt/configfile.js:125:27)
    at Object.config.get (/usr/local/haraka.matt/config.js:19:32)
    at Object.Server.load_smtp_ini (/usr/local/haraka.matt/server.js:22:25)
    at Object.<anonymous> (/usr/local/haraka.matt/server.js:40:8)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
```