Emil Velikov authored Jun 12, 2019 and Gert Wollny committed Jun 13, 2019

Currently we're using git clone --since=$GIT_DATE + git checkout $SHA
This causes problems when the $SHA is outside the time period.

Technically one can do git fetch origin $SHA, yet it requires a toggle
in git server-side. There is no obvious way to enable that in gitlab.

Alternatively we can (and should) update piglit and deqp on somewhat
regular intervals - just like we do for Mesa.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>