fix url encoding in redir

When redirecting to a page, ie, after editing, ensure that the url is
uri-encoded. Most browsers other than MSIE don't care, but it's the right
thing to do.

The known failure case involved editing a page that had utf-8 in the name
using MSIE.

IkiWiki/CGI.pm

@@ -40,7 +40,8 @@ sub showform ($$$$;@) {
 
 sub redirect ($$) {
 	my $q=shift;
-	my $url=shift;
+	eval q{use URI};
+	my $url=URI->new(shift);
 	if (! $config{w3mmode}) {
 		print $q->redirect($url);
 	}

debian/changelog

@@ -4,6 +4,9 @@ ikiwiki (3.20091024) UNRELEASED; urgency=low
   * mdwn: Avoid trying to use multimarkdown if it is not installed. 
   * moderatedcomments: New plugin to allow comment moderation w/o relying
     on blogspam.net.
+  * When redirecting to a page, ie, after editing, ensure that the
+    url is uri-encoded. Most browsers other than MSIE don't care, but it's
+    the right thing to do.
 
  -- Joey Hess <joeyh@debian.org>  Mon, 26 Oct 2009 11:53:32 -0400