Attach version_ to checkpoint path only if version is int

[yukw777]

Before submitting

• Was this discussed/approved via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• N/A Did you make sure to update the docs?
• Did you write any new necessary tests?
• If you made a notable change (that affects users), did you update the CHANGELOG?

What does this PR do?

Fixes #1659.

We should only attach the prefix version_ to the default checkpoint path when the logger's version is an integer.

PR review

Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in Github issues there's a high chance it will not be merged.

Did you have fun?

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[pep8speaks]

Hello @yukw777! Thanks for updating this PR.

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2020-05-06 15:25:13 UTC

[codecov]

Codecov Report

Merging #1748 into master will increase coverage by 0%.
The diff coverage is 100%.

@@          Coverage Diff           @@
##           master   #1748   +/-   ##
======================================
  Coverage      88%     88%           
======================================
  Files          69      69           
  Lines        4156    4157    +1     
======================================
+ Hits         3666    3667    +1     
  Misses        490     490