PlasmaShell should not be restored by the session manager. It will be
started by klauncher because we install an autostart file.
This also clears up the booting process to a certain extent, as
plasmashell will now not be started twice (once via session restore, and
once via autostart)
REVIEW: 119105
This reverts commit 30d2489930.
The test results we got indicate that on NVIDIA the problems with the
threaded rendering loop do not exist and at the same time the rendering
result improves a lot. As Qt still disables the threaded rendering loop
for the problematic drivers, it's better to not force the basic rendering
loop.