This test fails on OS X: we first fill sockets' kernel buffers and then
we tryto write a 'residue', waiting in 'select' for 2 seconds.
It looks like on OS X (at least, 10.10) 2 seconds are not enough - we always have a timeout.
Wait ... 4 seconds.
Change-Id: Id679dccda10b8f7859b8dfa6456b91ec13d52f68
Reviewed-by: Richard J. Moore <rich@kde.org>