Fix a bug occuring when pseudo-potentials do not have beta projectors
Fix a bug occuring when pseudo-potentials do not have beta projectors

toxa81/sirius,electronic-structure/sirius,toxa81/sirius,toxa81/sirius,electronic-structure/sirius,electronic-structure/sirius,toxa81/sirius,electronic-structure/sirius,electronic-structure/sirius,toxa81/sirius,electronic-structure/sirius,toxa81/sirius,electronic-structure/sirius