Fix endless loop of warnings in ServerWorker::_flushSocket()

[rdumusc]

@ppodhajski FYI - 10TB log file bug

[rdumusc]

For the record, relevant log extract

[...] {dock} bool FFMPEGMovie::_createAvFormatContext(const QString&): error reading movie headers: '/nfs4/bbp.epfl.ch/media/DisplayWall/hpc/exp_mario.mov' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Microsoft PowerPoint - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '2 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Microsoft PowerPoint - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '3 Microsoft PowerPoint - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '3 Microsoft PowerPoint - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '2 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '2 Microsoft PowerPoint - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain114.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '2 Keynote - bluebrain114.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Desktop - bluebrain114.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '2 Microsoft PowerPoint - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '3 Desktop - bluebrain114.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '2 Microsoft PowerPoint - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '2 Microsoft PowerPoint - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::closePixelStreamWindow(QString): closing pixel stream window: '1 Desktop - bluebrain219.epfl.ch' {master} void PixelStreamWindowManager::openWindow(const QString&, const QPointF&, const QSize&, bool): opening pixel stream window: '1 Desktop - bluebrain219.epfl.ch' QAbstractSocket::waitForBytesWritten() is not allowed in UnconnectedState QAbstractSocket::waitForBytesWritten() is not allowed in UnconnectedState QAbstractSocket::waitForBytesWritten() is not allowed in UnconnectedState [......]