[MITgcm-support] change hFac in mom_vecinv package

[Jean-Michel Campin]

Hi,

I will check-in few changes in the mom_vecinv package:
In order to use it with partial cell, I will replace few
S/R with the modified source from aim_5l_cs/code.
a) coriolis: no hFac
b) flux of relative vorticity: I keep the original form
(that was not working very well with partial cell)
within "IF ( use_original_hFac ) THEN / ENDIF" block, with
   PARAMETER ( use_original_hFac=.FALSE. )
and use the aim_5l_cs/code version as default. I don't have time
now to test other options (as, e.g, a formulation with no hFac).

I had to say that the new version is doing well on different tests
(exp4, enstrophy and energy conservation with z* in a SSH
adjustment problem with rotation or solid body rotation background flow)
and has been used for the atmosphere (both AIM & HS) with topography
for more than a year now without any problem.

These changes do not affect any verification/exp/ results
because none that uses VI has topography.

There might be some issue with TAF & the adjoint (sorry, Patrick).

Jean-Michel