[Reg] QXcbConnection:: no screens available

Regression introduced by:
https://codereview.qt-project.org/#/c/107504/

Reproducible with a remote connection from Windows (Xming/XLaunch) to Ubuntu. This is what I get on application startup:

QXcbConnection: Failed to get the primary output of the screen
QXcbConnection: no screen available
Abort (core dumped)

With earlier versions of Qt 5.x application did start up and worked as expected and output was the following:

QXcbConnection: Failed to get the primary output of the screen

Ubuntu has 2 screen connected.
Windows machine has 1 screen connected.