Remove redundant declarations and commmented-out code in ocn_comp_mcf.F

There are blocks of disused code in ocn_comp_mcf.F that have been left unattended for between four and eight years. I suggest it's time to remove these from the coupling code as part of a cleanup for V3, which will help make people's lives easier in the transition to Omega. Please look over [https://github.com/E3SM-Project/E3SM/blob/proteanplanet/ocean/cleanup-ocncompmct/components/mpas-ocean/driver/ocn_comp_mct.F and compare it to master](https://github.com/E3SM-Project/E3SM/compare/master...proteanplanet/ocean/cleanup-ocncompmct), and comment here as to whether you are happy with the removal of the commented-out code and the associated declarations that are unused. Please comment by this Friday, November 17, so that we can submit a BFB PR to master by next Monday, November 20, if all are in agreement for the removals.