[core] Repeated warning about Worker log file creation

[ijrsvt]

What is the problem?

On ray.init(), I get the following printed 16 times (one per worker it looks like).

(pid=<XXXX>) Could not create log file: File exists
(pid=<XXXX>) COULD NOT CREATE LOGFILE '20200621-222001.<XXXX>'!

Ray version and other system information (Python version, TensorFlow version, OS):
Python: 3.6.10
OS: MacOS 10.15.5
Latest Ray version (06/21/2020)

Reproduction (REQUIRED)

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• I have verified my script runs in a clean environment and reproduces the issue.
• I have verified the issue also occurs with the latest wheels.