Update Icepack tracer calls for recent refactor

[apcraig]

PR checklist

• Short (1 sentence) summary of your PR:
  Update Icepack tracer calls due to recent refactor
• Developer(s):
  apcraig, eclare
• Suggest PR reviewers from list in the column to the right.
• Please copy the PR test results link or provide a summary of testing completed below.
  TBD
• How much do the PR code changes differ from the unmodified code?
  • bit for bit
  • different at roundoff level
  • more substantial
• Does this PR create or have dependencies on Icepack or any other models?
  • Yes
  • No
• Does this PR add any new test cases?
  • Yes
  • No
• Is the documentation being updated? ("Documentation" includes information on the wiki or in the .rst files from doc/source/, which are used to create the online technical docs at https://readthedocs.org/projects/cice-consortium-cice/. A test build of the technical docs will be performed as part of the PR testing.)
  • Yes
  • No, does the documentation need to be updated at a later time?
    • Yes
    • No
• Please provide any additional information or relevant details below:

[eclare108213]

Let me know when you get this to compile and I will also run a test suite on badger. What version (or hash) are you doing regressions against?

[eclare108213]

In the icepack section of the developer guide, please change this sentence from

It does not directly “use” Icepack data and access Icepack data only thru interfaces.

to

It does not directly “use” Icepack data, accessing Icepack data only through interfaces.

[apcraig]

This version won't work until the Icepack PR is merged. You should be able to build a sandbox manually from this branch plus the v12a branch of Icepack off my fork. I have been comparing against CICE hash 38816ba as that was a master version for a couple weeks until recently.

[apcraig]

I updated the documentation as suggested.