SetLogFilenameExtension extension as a suffix to log file name

[gangadharmgithub]

Fix for #124.

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[gangadharmgithub]

I have signed the CLA

[googlebot]

CLAs look good, thanks!

[sammcj]

Can this please be merged if possible?

[YorkTsai2012]

@googlebot Why this PR is still not merged into master branch?

[sergiud]

googlebot does not merge anything. The PR has not been merged yet because no one reviewed the PR.

[dkteo]

@shinh PTAL

[sergiud]

Please resolve the conflict.