network: fix multi-phased NTLM authentication

tested manually with internal NTLM proxy.

Patch-by: Jonathan Lauvernier <Jonathan.Lauvernier@gmail.com>

Change-Id: Ib3ed7aff12cb8d59ffc2b11ecc1c4fdc04acb368
Reviewed-by: Richard J. Moore <rich@kde.org>
Doc: Added a new Qt Creator \externalpage

Change-Id: I9408e4e2c78b6e734b1478d570a5fc3d382fe124
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>