Slightly optimize memory usage of kccsd_rhf
Slightly optimize memory usage of kccsd_rhf

sunqm/pyscf,gkc1000/pyscf,sunqm/pyscf,gkc1000/pyscf,gkc1000/pyscf,sunqm/pyscf,sunqm/pyscf,gkc1000/pyscf,gkc1000/pyscf