org-indent: Fix "Fix line and wrap prefixes"

* lisp/org-indent.el (org-indent-set-line-properties): Fix
  wrap-prefix.

Reported-by: William Denton <wtd@pobox.com>
<http://lists.gnu.org/archive/html/emacs-orgmode/2017-06/msg00360.html>

lisp/org-indent.el

@@ -301,9 +301,8 @@ have `org-warning' face."
 	 (wrap
 	  (org-add-props
 	      (concat line
-		      (make-string level (if heading ?* ?\s))
-		      (if heading " "
-			(make-string (+ indentation (min level 1)) ?\s)))
+		      (if heading (concat (make-string level ?*) " ")
+			(make-string indentation ?\s)))
 	      nil 'face 'org-indent)))
     ;; Add properties down to the next line to indent empty lines.
     (add-text-properties (line-beginning-position) (line-beginning-position 2)