Problem with QtWidget in Jenkins

[avancinirodrigo]

It was removed in jenkins scripts commands that redirected the error out to dev/null, with this, there is a problem happening. The out is printing:

libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast
Unsupported screen depth: 8
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QPainter::save: Painter not active
QPainter::setPen: Painter not active
QPainter::drawRects: Painter not active
QPainter::restore: Unbalanced save/restore
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
Unsupported screen depth: 8
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QPainter::save: Painter not active
QPainter::setPen: Painter not active
.
.
.
<continue for hundreds lines>

Investigate it.

[avancinirodrigo]

This problem doesn't impact in installer. It seem only a problem in jenkins ubuntu VM, something associated to X11 and 'Unsupported screen depth'. @raphaelrpl This can help us: https://www.linuxquestions.org/questions/linux-general-1/change-screen-resolution-to-a-unsupported-mode-879465/

[avancinirodrigo]

This problem is associated to #1329. It was reported in stackoverflow: https://stackoverflow.com/questions/46432605/xvfb-extension-randr-missing-on-display-and-qt5