critical errors don't hit stderr

So I ran out of file descriptors earlier (not sure why as my limits.conf should allow enough) but I was oblivious of this fact (and the fact) that influxdb was not performing correctly because the stdout was pristine.

*log.txt* however told a much different story; showing how it could not write shard files and read them.  Really this should be in stdout as loosing something like this due to log rotation and lots of data in the log file is :(