ProjectExplorer: Fix SessionModel

... with regards to removal of a session, which was not reflected in the
view anymore.
Amends 8c0906e8fb.

Fixes: QTCREATORBUG-23547
Change-Id: Ibd9252719b9577e939781d69dd1c89fa819fff81
Reviewed-by: hjk <hjk@qt.io>

src/plugins/projectexplorer/sessionmodel.cpp

@@ -234,6 +234,7 @@ void SessionModel::deleteSessions(const QStringList &sessions)
         return;
     beginResetModel();
     SessionManager::deleteSessions(sessions);
+    m_sortedSessions = SessionManager::sessions();
     endResetModel();
 }