block: convert qcow/qcow2 to use generic cipher API Switch the qcow/qcow2 block driver over to use the generic cipher API, this allows it to use the pluggable AES implementations, instead of being hardcoded to use QEMU's built-in impl. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1435770638-25715-10-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>