CICE_RunMod: query 'Lsub' from Icepack

When CICE is compiled with the 'CICE_IN_NEMO' CPP macro, and 'calc_Tsfc'
is false, ice_step::coupling_prep calls CICE_RunMod::srcflux_to_ocn to
transfer heat fluxes on ice-free grid points to the ocean.

The calculation in srcflux_to_ocn uses the Icepack parameter 'Lsub', but
without declaring this variable nor querying it from Icepack, which
results in a compile-time failure when using the standalone driver with
'CICE_IN_NEMO' defined.

Fix that by correctly declaring 'Lsub' and querying it using the Icepack
interface.

cicecore/drivers/standalone/cice/CICE_RunMod.F90

@@ -628,11 +628,12 @@ subroutine sfcflux_to_ocn(nx_block,   ny_block,     &
 
       real (kind=dbl_kind)    :: &
           puny, &          !
+          Lsub, &          !
           rLsub            ! 1/Lsub
 
       character(len=*), parameter :: subname = '(sfcflux_to_ocn)'
 
-      call icepack_query_parameters(puny_out=puny)
+      call icepack_query_parameters(puny_out=puny, Lsub_out=Lsub)
       call icepack_warnings_flush(nu_diag)
       if (icepack_warnings_aborted()) call abort_ice(error_message=subname, &
          file=__FILE__, line=__LINE__)