Check default values for mocsy constants?

[andrew-c-ross]

The CO2 calculations have a few constants that can be set:

ocean_BGC/generic_tracers/FMS_ocmip2_co2calc.F90

Lines 59 to 61 in b1dd5ec

	character(len=3) :: boron_formulation = 'l10'
	character(len=3) :: dissociation_constants = 'm10'
	character(len=2) :: hf_equilibrium_constant = 'dg'

Sam has previously noted that the defaults are not what was recommended by Orr et al. 2015. After we make the changes in #72 we could check whether there should be any changes to these defaults.