Only copy cice_in to restart when using CICE4

[blimlim]

Closes #643

This PR modifies the access_esm1p6 driver so that it does not copy the cice_in.nml file to the restart directory when using CICE5. Behaviour with CICE4 is unchanged.

To test that there aren't any unintended effects, I've run 12 consecutive 1 month segments with and without the changes. Model outputs are identical according to the following:

(dev-payu-env) [sw6175@gadi-login-01 payu_cice_in]$ nccmp -dgf base/archive/output011/ice/iceh-1monthly-mean_2145-12.nc no_cice_in/archive/output011/ice/iceh-1monthly-mean_2145-12.nc 
(dev-payu-env) [sw6175@gadi-login-01 payu_cice_in]$ nccmp -dgf base/archive/output011/ice/iceh-1daily-mean_2145-12.nc no_cice_in/archive/output011/ice/iceh-1daily-mean_2145-12.nc

[coveralls]

coverage: 60.334% (+0.2%) from 60.174%
when pulling 2917723 on ACCESS-NRI:643-esm1.6-cice_in
into 0bda360 on payu-org:master.

[anton-seaice]

Looks good @blimlim - I suggest making a new issue to remove cice4 stuff (although I think im happy if we wait another month or two to action it, just in case)