ox-odt: Do not ignore org-odt-styles-file

* lisp/ox-odt.el (odt): Delete a repeated entry for :odt-styles-file
and absorb its org-odt-styles-file, which had no effect due to the
repeated entries, into the first definition.

TINYCHANGE

lisp/ox-odt.el

@@ -96,7 +96,7 @@
 	      (if a (org-odt-export-to-odt t s v)
 		(org-open-file (org-odt-export-to-odt nil s v) 'system))))))
   :options-alist
-  '((:odt-styles-file "ODT_STYLES_FILE" nil nil t)
+  '((:odt-styles-file "ODT_STYLES_FILE" nil org-odt-styles-file t)
     (:description "DESCRIPTION" nil nil newline)
     (:keywords "KEYWORDS" nil nil space)
     (:subtitle "SUBTITLE" nil nil parse)
@@ -110,7 +110,6 @@
     (:odt-inline-formula-rules nil nil org-odt-inline-formula-rules)
     (:odt-inline-image-rules nil nil org-odt-inline-image-rules)
     (:odt-pixels-per-inch nil nil org-odt-pixels-per-inch)
-    (:odt-styles-file nil nil org-odt-styles-file)
     (:odt-table-styles nil nil org-odt-table-styles)
     (:odt-use-date-fields nil nil org-odt-use-date-fields)
     ;; Redefine regular option.