scide: SingleInstanceGuard - prevent unnecessary warning

No need to flush() the QLocalSocket before waitForBytesWritten(),
or else an unnecessary warning may be posted if flush() has already
written all the pending data.
(cherry picked from commit 47e7f99)

editors/sc-ide/core/main.cpp

@@ -132,7 +132,6 @@ bool SingleInstanceGuard::tryConnect(QStringList const & arguments)
 
                 stream << QString("open");
                 stream << canonicalArguments;
-                socket->flush();
                 if (!socket->waitForBytesWritten(300))
                     qWarning("SingleInstanceGuard: writing data to another IDE instance timed out");