update to FatesPFTIndexSwapper.py

[rgknox]

Description:

These changes update FatesPFTIndexSwapper.py to accomodate the prt_organ dimension in the netcdf parameter files.

Collaborators:

@jkshuman

Expectation of Answer Changes:

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]

@jkshuman and I have both tested this update to the index swapper script and it appears to be working. This change set is trivial and will not impact any standard tests.
Integrating.