fix crash when tracker connections fails in the constructor (used to be the case for scrape when there were no url transform from announce to scrape)

include/libtorrent/http_tracker_connection.hpp

@@ -75,6 +75,7 @@ namespace libtorrent
 			, proxy_settings const& ps
 			, std::string const& password = "");
 
+		void start();
 		void close();
 
 	private:
@@ -92,6 +93,11 @@ namespace libtorrent
 
 		tracker_manager& m_man;
 		boost::shared_ptr<http_connection> m_tracker_connection;
+		session_settings const& m_settings;
+		address m_bind_iface;
+		proxy_settings const& m_ps;
+		connection_queue& m_cc;
+		io_service& m_ios;
 	};
 
 }

include/libtorrent/tracker_manager.hpp

@@ -194,6 +194,7 @@ namespace libtorrent
 
 		void fail(int code, char const* msg);
 		void fail_timeout();
+		virtual void start() = 0;
 		virtual void close();
 		address const& bind_interface() const { return m_bind_interface; }
 

include/libtorrent/udp_tracker_connection.hpp

@@ -74,6 +74,7 @@ namespace libtorrent
 			, session_settings const& stn
 			, proxy_settings const& ps);
 
+		void start();
 		void close();
 
 	private: