org.el: Fix a variable name error

* lisp/org.el (org-version): Fix an error imported with merge in
  f95641c443, replace `_version´ by `version1´.

lisp/org.el

@@ -311,7 +311,7 @@ When MESSAGE is non-nil, display a message with the version."
 	(if here
 	    (insert version)
 	  (message version))
-      (if message (message _version))
+      (if message (message version1))
       version1)))
 
 (defconst org-version (org-version))