Bug fix for NAG compiler issue in FatesHydroWTFMod

[glemieux]

Description:

This bugfix PR updates the psi_eff calculation to avoid an NAG compiler arithmetic exception error when a negative zero is raise to a power. This PR resolves #790.

Collaborators:

@rgknox

Expectation of Answer Changes:

Only when running in FatesHydro mode

Checklist:

• My change requires a change to the documentation.
• I have updated the in-code documentation .AND. (the technical note .OR. the wiki) accordingly.
• I have read the CONTRIBUTING document.
• FATES PASS/FAIL regression tests were run
• If answers were expected to change, evaluation was performed and provided

Test Results:

CTSM (or) E3SM (specify which) test hash-tag:

CTSM (or) E3SM (specify which) baseline hash-tag:

FATES baseline hash-tag:

Test Output:

[rgknox]

@glemieux why is there so much whitespace change? Was that intentional?

[glemieux]

@rgknox it wasn't intentional. One of the recent VSCode update changed something in one of the settings and now it auto-deletes trailing whitespace for what ever file I touch during commit. It's annoying; I need to track down the setting sometime soon to turn it off.

[ekluzek]

I do like the idea of getting rid of trailing whitespace. But, agree you want that to happen thoughtfully, and hopefully just in a commit that does that one thing. When you look at the PR you can turn off whitespace changes so that does help, or use "-w -b" to do it on the command line.

[rgknox]

I'm only concerned because we have several PRs currently out that change that module. I want to avoid conflicts and confusion with merges

[rgknox]

tests pass w/ expected fails:
/glade/scratch/rgknox/tests_1012-113133ch