decomp carbon pools are not calculated as expected

[peterdschwartz]

The code block in question is here:
ColumnDataType.F90 L7533

       if (use_pflotran .and. pf_cmode) then
          ! note: the follwoing should be useful to non-pflotran-coupled, but seems cause 1 BFB test unmatching.
          ! add up all vertical transport tendency terms and calculate total som leaching loss as the sum of these
          do l = 1, ndecomp_pools
             do fc = 1,num_soilc
                c = filter_soilc(fc)
                this%decomp_cpools_leached(c,l) = 0._r8
             end do
             do j = 1, nlev
                do fc = 1,num_soilc
                   c = filter_soilc(fc)
                   this%decomp_cpools_leached(c,l) = &
                     this%decomp_cpools_leached(c,l) + &
                     this%decomp_cpools_transport_tendency(c,j,l) * dzsoi_decomp(j)
                end do
             end do
             do fc = 1,num_soilc
                c = filter_soilc(fc)
                this%som_c_leached(c) = &
                   this%som_c_leached(c) + &
                   this%decomp_cpools_leached(c,l)
             end do
          end do
       end if

Above, the col_cf%decomp_cpools_leached and col_cf%som_c_leached are only calculated with pflotran. This is inconsistent with the corresponding Nitrogen and Phosphorus pools so this is likely a bug.

Removing the if block yields DIFFs in these tests:

  ERS.r05_r05.ICNPRDCTCBC.pm-cpu_intel.elm-cbudget (Overall: DIFF) details:
  SMS_Ln9.ne4pg2_oQU480.F2010.pm-cpu_intel.eam-outfrq9s (Overall: DIFF) details:
  SMS_Ly2_P1x1.1x1_smallvilleIA.IELMCNCROP.pm-cpu_intel.elm-fan (Overall: DIFF) details:
  SMS_Ly2_P1x1.1x1_smallvilleIA.IELMCNCROP.pm-cpu_intel.elm-force_netcdf_pio (Overall: DIFF) details:
  SMS_Ly2_P1x1.1x1_smallvilleIA.IELMCNCROP.pm-cpu_intel.elm-per_crop (Overall: DIFF) details:
  SMS_Ly2_P1x1_D.1x1_smallvilleIA.IELMCNCROP.pm-cpu_intel.elm-lulcc_sville (Overall: DIFF) details:

[peterdschwartz]

Level of diffs for some of the tests. The small absolute value may be due to initial conditions? Relative differences seem significant.

 **SMS_Ln9.ne4pg2_oQU480.F2010.pm-cpu_intel.eam-outfrq9s**
 RMS CMASS_BALANCE_ERROR              1.7722E-16          NORMALIZED  1.6872E+00
 RMS M_LITR1C_TO_LEACHING             1.0034E-24            NORMALIZED  4.3958E+00
 RMS M_LITR2C_TO_LEACHING             1.9482E-24            NORMALIZED  4.7792E+00
 RMS M_LITR3C_TO_LEACHING             1.0670E-24            NORMALIZED  4.8193E+00

**SMS_Ly2_P1x1.1x1_smallvilleIA.IELMCNCROP.pm-cpu_intel.elm-per_crop**
 RMS M_LITR1C_TO_LEACHING             6.2391E-20            NORMALIZED  2.0000E+00
 RMS M_LITR2C_TO_LEACHING             9.9899E-20            NORMALIZED  2.0000E+00
 RMS M_SOIL2C_TO_LEACHING             1.2005E-19            NORMALIZED  2.0000E+00
 RMS M_SOIL4C_TO_LEACHING             2.6632E-20            NORMALIZED  2.0000E+00