[O] update to ob-clojure.el

[Oleh]

Hi all,

I've made an update to ob-clojure.el, which wasn't working for me with
the new cider (the required function was removed).

I haven't looked into 'nrepl or 'slime options for evaluation, is
anyone using them?

Eric, should 'nrepl option be removed as obsolete? And maybe 'slime as well?

regards,
Oleh