Stop tracking the session/profile pair after a session is closed.

The patch(slightly modified) is from Gu Rui <chaos.proton@gmail.com>

REVIEW: 102507

src/SessionManager.cpp

@@ -353,6 +353,9 @@ void SessionManager::sessionTerminated(QObject* sessionObject)
     Q_ASSERT( session );
 
     _sessions.removeAll(session);
+    _sessionProfiles.remove(session);
+    _sessionRuntimeProfiles.remove(session);
+
     session->deleteLater();
 }