Deprecated usage of `scipy.optimize.optimize import OptimizeResult`

[vprusso]

In files hartree_fock_test.py and hartree_fock.py the import pattern of

from scipy.optimize.optimize import OptimizeResult

yields the following deprecation warning:

DeprecationWarning: Please use `OptimizeResult` from the `scipy.optimize` namespace, the `scipy.optimize.optimize` namespace is deprecated.

The fix for this should simply be to alter from scipy.optimize.optimize import OptimizeResult to from scipy.optimize import OptimizeResult in both the hartree_fock.py and hartee_fock_test.py files to eliminate this warning.

[fdmalone]

Closing following merging of #811.