Latent heat bug in COARE atm/ocn flux routine for CESM

In the CESM COARE atmosphere-ocean flux calculations, the surface latent heat flux[ is calculated like so](https://github.com/ESCOMP/CMEPS/blob/main/cesm/flux_atmocn/flux_atmocn_COARE_mod.F90#L402):

> hlb=-rhoa * Le * usr * qsr

With the `Le` variable representing the latent heat of vaporization, and the rest of the terms combining to be the surface evaporation (water vapor mass) flux. In COARE `Le` is the "constant" latent heat of vaporization with an applied [ocean surface temperature adjustment](https://github.com/ESCOMP/CMEPS/blob/main/cesm/flux_atmocn/flux_atmocn_COARE_mod.F90#L292):

> Le = loc_latvap - .00237e6_R8 * (ts-273.16_R8)

where `loc_latvap` is the constant value, and `ts` is the ocean surface temperature. The latent heat flux (`hlb`) term is then passed out from COARE, and converted back into an evaporation flux for use by CESM. However, that conversion doesn't use the the temperature-adjusted `Le` variable, but instead [the constant value](https://github.com/ESCOMP/CMEPS/blob/main/cesm/flux_atmocn/flux_atmocn_COARE_mod.F90#L189):

> evap(n) = lat(n)/loc_latvap

where `lat(n)` is the same as `hlb`. This results in an `Le/loc_latvap`, or `1 - .00237e6_R8 * (ts-273.16_R8)/loc_latvap`, bias in the evaporation flux to CESM relative to what COARE actually predicts.

The fix is either to just pass `evap` out directly from COARE, or simply use `Le` instead of `loc_latvap` in the lat->evap conversion.

Credit goes to Benjamin Barr for confirming the existence of the bug!