torrent-index use '-' for unknown/empty values

deluge/ui/webui/webui_plugin/templates/advanced/index.html

@@ -100,19 +100,28 @@ $for torrent in torrent_list:
     </td>
     $if (not get('category')):
         <td>$torrent.category</td>
-    <td>$torrent.num_seeds ($torrent.total_seeds)</td>
-    <td>$torrent.num_peers ($torrent.total_peers)</td>
+    <td>
+    $if torrent.total_seeds != -1:
+        $torrent.num_seeds ($torrent.total_seeds)
+    $else:
+        -
+    </td>
+    <td>
+    $if torrent.total_peers != -1:
+        $torrent.num_peers ($torrent.total_peers)</td>
+    $else:
+        -
     <td>
     $if (torrent.download_rate):
         $fspeed(torrent.download_rate)
     $else:
-        &nbsp;
+        -
     </td>
     <td>
     $if (torrent.upload_rate):
         $fspeed(torrent.upload_rate)
     $else:
-        &nbsp;
+       -
     </td>
     <td>$ftime(torrent.eta)</td>
     <td>$("%.3f" % torrent.distributed_copies)</td>