Revert back to updating etaN only when initial ssh is part of control. Updating etaH as well caused failed ADM test using gfortran with -devel option for the global_ocean.90x40x15 experiments.
Revert back to updating etaN only when initial ssh is part of control. Updating etaH as well caused failed ADM test using gfortran with -devel option for the global_ocean.90x40x15 experiments.

altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h,altMITgcm/MITgcm66h