Launcher socket: Replace an assertion with a proper check
Launcher socket: Replace an assertion with a proper check

Calls to sendData() can legitimately come in even after the socket has
failed, because the potential callers live in a different thread.

Change-Id: I6bfdf20e723ebe089bb9e49d294ae434eefeabbc
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@qt.io>

qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs