Enable building on old kernels
    
    This adds scripts that mock sha512hmac and fipshmac using openssl. These
    are used instead of the built hashers to hash libkcapi binaries on
    kernels that don't suport the userspace Crypto API interface properly
    (e.g. RHEL-7 kernels).
    
    Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>