linkmap, pagestats: avoid using %links to get a list of pages

When a page is deleted, it is removed from %pagesources, but
not from %links. So use the former.

IkiWiki/Plugin/linkmap.pm

@@ -56,7 +56,7 @@ sub genmap ($) {
 
 	# Get all the items to map.
 	my %mapitems = ();
-	foreach my $item (keys %links) {
+	foreach my $item (keys %pagesources) {
 		if (pagespec_match($item, $params{pages}, location => $params{page})) {
 			$mapitems{$item}=urlto($item, $params{destpage});
 		}

IkiWiki/Plugin/pagestats.pm

@@ -45,7 +45,7 @@ sub preprocess (@) {
 	
 	my %counts;
 	my $max = 0;
-	foreach my $page (pagespec_match_list([keys %links],
+	foreach my $page (pagespec_match_list([keys %pagesources],
 			$params{pages}, location => $params{page})) {
 		use IkiWiki::Render;