[Development] [Packaging] Backport fixes for QNAM corruption

[Daniel Molkentin]

Hi,

We have identified a data corruption in QNetworkAccessManager affecting
all currently supported versions of Qt. Fixes have been provided for Qt
5.4 [1] and Qt 4.8 [2], and will be part of Qt 5.4.7 and Qt 4.8.2
respectively. The commit message also details on the nature of the
upload corrution. They should apply to older versions of Qt 4 and 5 as well.

As there is no sensible workaround for this problem, I would like to
urge packagers to consider adding this patch to Qt for their existing
distributions. Since the fixes are accompanied by auto tests that
validate their correctness, the risk of this patch is very low, with the
advantages outweighing them by far.

Cheers,
  Daniel

[1] https://codereview.qt-project.org/#/c/110150/
[2] https://codereview.qt-project.org/#/c/111363/