fixed nat-pmp bug

ChangeLog

@@ -92,6 +92,7 @@ release 0.14.8
 	  sometimes be used incorrectly
 	* force_recheck() no longer crashes on torrents with no metadata
 	* fixed broadcast socket regression from 0.14.7
+	* fixed hang in NATPMP when shut down while waiting for a response
 
 release 0.14.7
 

src/natpmp.cpp

@@ -586,6 +586,7 @@ void natpmp::close_impl(mutex::scoped_lock& l)
 	}
 	error_code ec;
 	m_refresh_timer.cancel(ec);
+	m_currently_mapping = -1;
 	update_mapping(0, l);
 }