thermophysicalModels: Corrected alphah to be enthalpy based

in

solidSpecie/transport/const/constAnIsoSolidTransport
solidSpecie/transport/const/constIsoSolidTransport
solidSpecie/transport/exponential/exponentialSolidTransport
solidSpecie/transport/polynomial/polynomialSolidTransport
specie/transport/logPolynomial/logPolynomialTransport
specie/transport/polynomial/polynomialTransport
specie/transport/sutherland/sutherlandTransport

Resolves bug-report https://bugs.openfoam.org/view.php?id=2532