forward port SVN commit 909480 by woebbe:

set MAX_PACKET_LEN to 8192 to workaround two bugs:

1. nntp: if a line is longer than MAX_PACKET_LEN the rest isn't read
2. TCPSlaveBase::readLine(): in that case -1 is returned as QIODevice::readLine() reads only maxSize - 1 (one byte less for terminating '\0') and TCPSlaveBase::readLine() calls QIODevice::readLine() for one byte, but QIODevice::readLine() needs at least 2.

CCMAIL:vkrause@kde.org
CCMAIL:ahartmetz@gmail.com

Volker, Andreas, is memset() really needed before calling TCPSlaveBase::readLine()?

Andreas, could you please extent the docu of TCPSlaveBase::readLine() (e.g. what happens
if the line is longer than len).

svn path=/trunk/KDE/kdepimlibs/; revision=923507