integritysetup: do not use crypt_init_data_device after crypt_init
    
    crypt_init_data_device() replaces the crypt_device struct with a
    new allocation, losing the old one, which we get from crypt_init().
    Use crypt_set_data_device() instead.
    
    Enhance the test to cover this option too.
    
    (cherry picked from commit 872f9da4d8b67b012f1b1b227416d0c99bcdf43c)