ob-ruby: only require inf-ruby when absolutely necessary

* lisp/ob-ruby.el (org-babel-expand-body:ruby): removed requirement of
  inf-ruby

lisp/ob-ruby.el

@@ -54,7 +54,6 @@
 
 (defun org-babel-expand-body:ruby (body params &optional processed-params)
   "Expand BODY according to PARAMS, return the expanded body."
-  (require 'inf-ruby)
   (let ((vars (nth 1 (or processed-params (org-babel-process-params params)))))
     (concat
      (mapconcat ;; define any variables