mask restoring variables

[eclare108213]

The restoring variables needed to be masked by land, and restart_ext must be true when using open boundaries, so that the halo cells are saved in the restart files.

• Developer(s): E. Hunke

• Please suggest code Pull Request reviewers in the column at right.

• Are the code changes bit for bit, different at roundoff level, or more substantial? BFB except for the test that was failing.

• Is the documentation being updated with this PR? (Y/N) N
  If not, does the documentation need to be updated separately at a later time? (Y/N) N
  Note: "Documentation" includes information on the wiki and .rst files in doc/source/,
  which are used to create the online technical docs at https://readthedocs.org/projects/cice-consortium-cice/.

• Other Relevant Details:
  Addresses issue boxrestart test is failing exact restart #138. I still need to run the base_suite.

[apcraig]

These look fine, why is travis failing?

[eclare108213]

travis is failing on the builds because I'm multiplying real arrays by tmask, which is a logical array. I need to use hm instead, or convert tmask to real (double) locally.

[eclare108213]

@apcraig, this should be ready to merge now