The UUID operations we need from libuuid are fully supported by QEMU UUID
implementation. Use it, and remove the unused code.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-Id: <1474432046-325-5-git-send-email-famz@redhat.com>