Access "alphas" while "alphas" are removed.

Hi Alec,

When I was running examples/Fock_prep_ECD_opt.ipynb, analysis.print_info() throws an error which shows “alphas” is missing in .h5 file. 
I looked into your commit cbd44bc with comment “removed use_displacements and alphas” where alphas are removed when saving to h5 file, but alphas are not removed in ECD_control/ECD_optimization/optimization_analysis.py’s line 68, 159, 200.