set open-paren-in-column-0-is-defun-start to nil buffer-local in clojure-mode, fixes gh-183, fixes gh-140

/ht to @tsdh for gently prodding with the hints about buffer-local settings, etc. Turns out clojure-mode is already using `setq-local` all over the place.. Should stop walking on eggshells with the elisp, I guess. :-)