Don't call fs.existsSync and then immediately call fs.lstatSync

[rcombs]

See: https://github.com/shama/gaze/blob/master/lib/gaze.js#L388
existsSync makes a stat syscall, and then lstatSync makes an lstat syscall. This is redundant and a waste of time. Just call fs.lstatSync and handle the exception if the file doesn't exist. This also solves your race condition between the two calls, which currently results in an exception being thrown out of the map call.