Properly set evaporation 'cflx' index

[nusbaume]

Tag name (required for release branches):
Originator(s): nusbaume

Description (include the issue title, and the keyword ['closes', 'fixes', 'resolves'] followed by the issue number):

Ensures that the cflx constituent index for surface evaporation matches the constituents' array index for water vapor. This change is needed before the changes in ESCOMP/atmospheric_physics#267 are brought into CAM-SIMA (otherwise the new physics schemes may not work as expected).

Fixes #414

Describe any changes made to build system: N/A

Describe any changes made to the namelist: N/A

List any changes to the defaults for the input datasets (e.g. boundary datasets): N/A

List all files eliminated and why: N/A

List all files added and what they do: N/A

List all existing files that have been modified, and describe the changes:
(Helpful git command: git diff --name-status development...<your_branch_name>)

M src/cpl/nuopc/atm_import_export.F90

• Set evaporation cflx index to match CCPP constituent array index for water vapor.

If there are new failures (compared to the test/existing-test-failures.txt file),
have them OK'd by the gatekeeper, note them here, and add them to the file.
If there are baseline differences, include the test and the reason for the
diff. What is the nature of the change? Roundoff?

derecho/intel/aux_sima: ALL PASS

derecho/gnu/aux_sima: ALL PASS

If this changes climate describe any run(s) done to evaluate the new
climate in enough detail that it(they) could be reproduced:

CAM-SIMA date used for the baseline comparison tests if different than latest:

[jimmielin]

Thanks @nusbaume!