Don't attempt to update expired if we switched playlists (renditions)

There is no guarantee that different playlists have the same media-sequence number in a live stream. This would throw off expired calculations and make all our times useless. The fetcher should eventually fetch a segment with timing information and that will bring our expired calculation back in line.

@@ -360,6 +360,10 @@
       return;
     }
 
+    if (update.uri !== outdated.uri) {
+      return;
+    }
+
     // try using precise timing from first segment of the updated
     // playlist
     if (update.segments.length) {