Fix s3.get(path, { file : somePath }) not closing file on error

Closes #85

I used `called` variable here, because when calling destroy, it will end up called `end` event of file, which will call the call the callback, but that's not what we want.

I have tested this with node v0.8.25 and v0.10.13, and it passes the s3-get tests(as I mentioned, some tests fail without modifications on my system, aside those no failing tests).