Use add-to-list instead of push in gnus-1

to avoid duplicate entries.

lisp/gnus/ChangeLog

@@ -1,3 +1,7 @@
+2012-02-16  Leo Liu  <sdl.web@gmail.com>
+
+	* gnus-start.el (gnus-1): Avoid duplicate entries.
+
 2012-02-15  Lars Ingebrigtsen  <larsi@gnus.org>
 
 	* shr.el (shr-remove-trailing-whitespace): Really delete the padding on

lisp/gnus/gnus-start.el

@@ -763,8 +763,8 @@ prompt the user for the name of an NNTP server to use."
     ;; Add "native" to gnus-predefined-server-alist just to have a
     ;; name for the native select method.
     (when gnus-select-method
-      (push (cons "native" gnus-select-method)
-	    gnus-predefined-server-alist))
+      (add-to-list 'gnus-predefined-server-alist
+		   (cons "native" gnus-select-method)))
 
     (if gnus-agent
 	(gnus-agentize))