back-port torrent peer-class fix from master

ChangeLog

@@ -1,5 +1,6 @@
 1.1.1 release
 
+	* fixed peer-class leak when settings per-torrent rate limits
 	* added a new "preformatted" type to bencode entry variant type
 	* improved Socks5 support and test coverage
 	* fix set_settings in python binding

simulation/libsimulator

@@ -1 +1 @@
-Subproject commit ea3bffe3c53bca5e0976914ea951193ba43fbed6
+Subproject commit ad23c932ecd852f89c7d8b29dfe162e9ee073a1b

src/torrent.cpp

@@ -970,6 +970,7 @@ namespace libtorrent
 		// this means that the invariant check that this is called from the
 		// network thread cannot be maintained
 
+		TORRENT_ASSERT(m_peer_class == 0);
 		TORRENT_ASSERT(m_abort);
 		TORRENT_ASSERT(m_connections.empty());
 		if (!m_connections.empty())
@@ -4936,6 +4937,12 @@ namespace libtorrent
 		update_gauge();
 		stop_announcing();
 
+		if (m_peer_class > 0)
+		{
+			m_ses.peer_classes().decref(m_peer_class);
+			m_peer_class = 0;
+		}
+
 		error_code ec;
 		m_inactivity_timer.cancel(ec);