renamed pcmdi_metrics_driver to mean_climate_driver

[doutriaux1]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 521

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 35.328%

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Totals
Change from base Build 517:	0.0%
Covered Lines:	909
Relevant Lines:	2573

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💛 - Coveralls

[zshaheen]

It looks good.

Sometimes when renaming files like this, I forget to remove the build folder, so the old name still works. Uninstalling, removing that folder and reinstalling makes it all good.