Errors in rename_feed_tag and rename_tag

There were a couple of errors in these two subs. Here is a greader.pl which prints the error messages.

	#!/usr/bin/env perl

	use 5.14.0;
	use lib '/Users/jean/Developpement/Essais/webservice-google-reader/lib';
	use strict;
	use warnings;

	use WebService::Google::Reader;

	my $reader = WebService::Google::Reader->new(
	   username => $ENV{GOOGLE_USERNAME},
	   password => $ENV{GOOGLE_PASSWORD},
	);

	my $action = shift or die "No action";
	my ( $old, $new ) = @ARGV;

	given ($action) {

	   when (/--rename_feed_tag/) {

	       # greader.pl --rename_feed_tag foo bar

	       eval { $reader->rename_feed_tag( $old, $new ); };
	       print $@;

	       # Can't locate object method "categories" via package "WebService::Google::Reader"

	   }
	   when (/--rename_tag/) {

	       # greader.pl --rename_tag foo bar

	       eval { $reader->rename_tag( $old, $new ); };
	       print $@;

	       # Can't locate object method "rename_tag_feed" via package "WebService::Google::Reader"

	   }

	}