Pass salt flux restoring/correction to generic tracers

[dougiesquire]

See #389 for context and details.

Reiterating from that issue:
These changes should not alter the current behaviour of MOM5 if the generic_tracer code in the local ocean_shared directory is used. However, if an external generic_tracer codebase is used (e.g. NOAA-GFDL/ocean_BGC), that code will need to include the new generic_tracer::generic_tracer_update_from_coupler routine. There is currently an open PR to add this routine to NOAA-GFDL/ocean_BGC.

Closes #389

[dougiesquire]

I don't have permission to request a review. @russfiedler, @aidanheerdegen, @aekiss, anyone pleeease?

[dougiesquire]

@nikizadehgfdl might you have time to review this? We're struggling to find reviewers with the necessary background knowledge of generic tracers and your eyes would be much appreciated.

These are the changes required to allow NOAA-GFDL/ocean_BGC#35

[dougiesquire]

Is there anyone out there that would be able to review?

[aekiss]

Sorry, I don't know nearly enough of the nuts and bolts to give a meaningful review.

[aidanheerdegen]

@marshallward I've pinged you for a review, but if this isn't your thing feel free to rope in someone from GFDL who might know more.

THANKS!

[marshallward]

Definitely not my thing, but I will see if anyone here has the time to look. Otherwise, I'll try to make sense of it.

[aidanheerdegen]

Definitely not my thing, but I will see if anyone here has the time to look. Otherwise, I'll try to make sense of it.

Thanks @marshallward

[theresa-morrison]

@dougiesquire I took a look at this, but I am much more familiar with MOM6. I can follow the logic here and it seems to be doing what you laid out in the issuse. I can't do any testing but I can provide a review if looking at the code is sufficient for you.

[aidanheerdegen]

@dougiesquire I took a look at this, but I am much more familiar with MOM6. I can follow the logic here and it seems to be doing what you laid out in the issuse. I can't do any testing but I can provide a review if looking at the code is sufficient for you.

@dougiesquire is on parental leave, so in case he doesn't see this, yes please! Dougie has done a lot of testing, but I think he really wanted a sanity check to make sure there wasn't anything obvious he hadn't taken into account.

[theresa-morrison]

I have reviewed this code by reading it and the associated issue. I think that it accomplishes the goal, but I have not been able to test it. I expect that these changes will not cause problems if you are running MOM5 without the salt flux turned on.