File download hang fix

[krnowak]

Fixes SOAP-77.

[dfaure-kdab]

A fix with a unittest - great!

Just two comments:

1. the file_download.txt could be created once, by doing it in the _data method, rather than doing it every time the testFileDownload() method is called.
2. rather than a bool "expectedSuccess", it should be the actual expected error() value. It would allow a more precise QCOMPARE instead of the QVERIFY((int)reply->error() != (int)QNetworkReply::NoError);

Thanks.

[krnowak]

Ad 1) It was mostly a copy of the old testFileDownload (now renamed to testFileDownloadAuth). Also, I don't see a way to call per-test cleanup. There is only general init/cleanup (called before/after every test) and similar for entire test case.

Ad 2) I made it a bool, because I would expect that "readable" case returns NoError, "nonexistent" - ContentNotFoundError and "unreadable" - ContentOperationNotPermittedError as per http://qt-project.org/doc/qt-5.0/qtnetwork/qnetworkreply.html#NetworkError-enum

But for now the code in KDSoapServerSocket just returns UnknownContentError for last two. I could, for example, modify file download handling that if it gets NULL QIODevice then it returns 404 or if it gets it but cannot open for reading then it returns 403 (see new commit anyway). But that makes yet another test case failure. Not sure how to proceed here.