ox-odt: Fix exporting target link without a description

* lisp/ox-odt.el (org-odt-link--infer-description): Fix comment.
(org-odt-link): When link to target has no description, use a number.

Reported-by: Christian Moe <mail@christianmoe.com>
<http://permalink.gmane.org/gmane.emacs.orgmode/94815>

lisp/ox-odt.el

@@ -2610,11 +2610,12 @@ Return nil, otherwise."
 			 (t nil))))))))
 
 (defun org-odt-link--infer-description (destination info)
-  ;; DESTINATION is a HEADLINE, a "<<target>>" or an element (like
-  ;; paragraph, verse-block etc) to which a "#+NAME: label" can be
-  ;; attached.  Note that labels that are attached to captioned
-  ;; entities - inline images, math formulae and tables - get resolved
-  ;; as part of `org-odt-format-label' and `org-odt--enumerate'.
+  ;; DESTINATION is a headline or an element (like paragraph,
+  ;; verse-block etc) to which a "#+NAME: label" can be attached.
+
+  ;; Note that labels that are attached to captioned entities - inline
+  ;; images, math formulae and tables - get resolved as part of
+  ;; `org-odt-format-label' and `org-odt--enumerate'.
 
   ;; Create a cross-reference to DESTINATION but make best-efforts to
   ;; create a *meaningful* description.  Check item numbers, section
@@ -2770,11 +2771,10 @@ INFO is a plist holding contextual information.  See
 	  (target
 	   ;; If there's a description, create a hyperlink.
 	   ;; Otherwise, try to provide a meaningful description.
-	   (if (not desc) (org-odt-link--infer-description destination info)
-	     (let ((label (org-element-property :value destination)))
-	       (format "<text:a xlink:type=\"simple\" xlink:href=\"#%s\">%s</text:a>"
-		       (org-export-solidify-link-text label)
-		       desc))))
+	   (let ((label (org-element-property :value destination)))
+	     (format "<text:a xlink:type=\"simple\" xlink:href=\"#%s\">%s</text:a>"
+		     (org-export-solidify-link-text label)
+		     (or desc (org-export-get-ordinal destination info)))))
 	  ;; Case 4: Fuzzy link points to some element (e.g., an
 	  ;; inline image, a math formula or a table).
 	  (otherwise