Remove self-assignments

In lines 587-589, a variable is getting assigned to itself, which is probably an error:

```python
    else:
        delta_gs = [g_vectors] * num_kpts
        g_mapping = g_mapping
```

Around lines 912-917, the same thing happens with another variable:

```python
    elif kmeans_weighting_function == "sum_squares":
        # w(r) = sum_{i} |phi_{ki}(r)|
        weighting_function = np.einsum(
            "kRi,kRi->R", bloch_orbitals_mo.conj(), bloch_orbitals_mo, optimize=True
        )
        weighting_function = weighting_function
```

Author: mhucka

src/openfermion/resource_estimates/pbc/thc/factorizations/isdf.py

@@ -586,7 +586,6 @@ def kpoint_isdf_double_translation(
         delta_gs = delta_gs_unique
     else:
         delta_gs = [g_vectors] * num_kpts
-        g_mapping = g_mapping
     zeta = np.zeros((num_kpts,), dtype=object)
     for iq in range(num_kpts):
         num_g = len(delta_gs[iq])
@@ -914,7 +913,6 @@ def solve_kmeans_kpisdf(
         weighting_function = np.einsum(
             "kRi,kRi->R", bloch_orbitals_mo.conj(), bloch_orbitals_mo, optimize=True
         )
-        weighting_function = weighting_function
     else:
         raise ValueError(f"Unknown value for weighting function {kmeans_weighting_function}")
     interp_indx = kmeans.find_interpolating_points(