Salinity flux does not go to zero when SSS = 0.

[dabail10]

The code here needs a fix for coupled models when sea surface salinity goes to 0. In fact, this should probably stop taking salt from the ocean when SSS = S_min, currently 0.1.

Icepack/columnphysics/icepack_therm_mushy.F90

Lines 2921 to 2925 in f6ff8f7

	k = nilyr
	zSin(k) = zSin(k) + max(S_min - zSin(k), &
	((q(k) * (sss - Sbr(k))) / hilyr + &
	dSdt(k) + &
	(w * (Sbr(k-1) - Sbr(k))) / hilyr) * dt)