Trying to upload vocabulary an error popup prevents from opening the upload dialog.

In specific, in console output I see:
"Cannot lock file /tmp/parley-uTj2pFc1.kvtml"

So as to overcome the issue, in parleydocument.cpp, in uploadFile(), I changed :
    if ( m_doc->saveAs(url, KEduVocDocument::Automatic) != KEduVocDocument::NoError ){
to
    if ( tempDoc.open(url, KEduVocDocument::FileIgnoreLock) != KEduVocDocument::NoError ) {

Now, upload dialog opens as expected.
But when I try to pass my credentials and login to opendesktop I get in console:

content-type missing in HTTP POST, defaulting to application/x-www-form-urlencoded. Use QNetworkRequest::setHeader() to fix this problem.

In UI I get a popup saying 'Could not verify login, please try again.'

Then I changed uploadFile again, setting 
from
KNS3::UploadDialog dialog(ParleyMainWindow::instance());
to
KNS3::UploadDialog dialog(QStringLiteral("parley-themes.knsrc"),ParleyMainWindow::instance() );

so as to force the usage of ProvidersUrl=http://download.kde.org/ocs/providers.xml that parley-themes.knsrc contains instead of ProvidersUrl=http://edu.kde.org/parley/newstuff/providers44.xml that parley.knsrc uses.

Now, I can follow the whole of steps of the upload dialog, but upload fails in the end.

TBH, after opendesktop revamp I am not quite sure where vocabulary files can be found or under what category.

Reproducible: Always

Steps to Reproduce:
1. Select a vocabulary collection
2. Open editor
3. Try to upload the collection

Actual Results:  
Vocabulary is not uploaded

Expected Results:  
Vocabulary to be uploaded