server error messages flood stderr

[hsuyeep]

In automating aartfaac-server, we would like to store the stdout/stderr in log files for analysis of breakdowns. Currently, aartfaac-server generates messages like
'[WARNING] [aartfaac-server-41027] QAbstractSocket::waitForBytesWritten() is not allowed in UnconnectedState', probably when a pipeline severs its connection. However, the message is written out within a busy loop, resulting in very large log files. Such connections should time out and retry after a reasonable period, probably with a more informative error message.