Attempt to use PATCH method results in error:
Unsupported HTTP method type

Most probably two files need attention:
./qtbase/src/network/access/qnetworkaccessmanager.cpp
Few lines copy-paste from other methods.

./qtdeclarative/src/qml/qml/qqmlxmlhttprequest.cpp
Oneliner, just allow the PATCH method.

http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol
PATCH - Is used to apply partial modifications to a resource.