fix crash in force_recheck for torrents with no metadata

ChangeLog

@@ -88,6 +88,7 @@ release 0.14.8
 	* fixed typo that would sometimes prevent queued torrents to be checked
 	* fixed bug in auto-manager where active_downloads and active_seeds would
 	  sometimes be used incorrectly
+	* force_recheck() no longer crashes on torrents with no metadata
 
 release 0.14.7
 

src/torrent.cpp

@@ -1016,6 +1016,8 @@ namespace libtorrent
 
 	void torrent::force_recheck()
 	{
+		if (!valid_metadata()) return;
+
 		// if the torrent is already queued to check its files
 		// don't do anything
 		if (should_check_files()