Distil the body of the org-to-gfm hook function

1. We can condense 6 lines into 1, the prior code is overcomplicated
2. The refactor by @hlissner can actually trigger the error "Cannot
   replace a buffer with itself"

emacs-everywhere.el

@@ -435,12 +435,7 @@ Should end in a newline to avoid interfering with the buffer content."
              (emacs-everywhere-markdown-p))
     (goto-char (point-min))
     (insert emacs-everywhere-org-export-options)
-    (let ((export-buffer (generate-new-buffer "*Emacs Everywhere Export*"))
-          org-export-show-temporary-export-buffer) ; don't create a split!
-      (unwind-protect
-          (replace-buffer-contents
-           (org-export-to-buffer (if (featurep 'ox-gfm) 'gfm 'md) (current-buffer)))
-        (kill-buffer export-buffer)))))
+    (org-export-to-buffer (if (featurep 'ox-gfm) 'gfm 'md) (current-buffer))))
 
 (provide 'emacs-everywhere)
 ;;; emacs-everywhere.el ends here