Revert "org-compat.el: New compatibility function `org-random'"
This reverts commit 7719734dd7b216e29ee7f5be5077d13004903a7d.
* lisp/org-id.el: Do not use (random t), we just want a new random
number, not a re-seeding of the PRNG for which (random t) doesn't
provide enough entropy anyway. Even if (random) would always
produce the same sequence, the other components going into the MD5
hash ensure that the result will be unique.