Avoid race during button-triggered DPMS
Review Request #106795 - Created Oct. 11, 2012 and submitted
Avoid race during button-triggered DPMS core->onResumeFromSuspend calls SimulateUserActivity from the screensaver dbus interface. This seems to race with the subsequent call to DPMSForceLevel so that the screen re-wakes but 'xset -q' thinks it is off and timed dpms activation is disabled (this may be hardware dependent - see https://bugzilla.redhat.com/show_bug.cgi?id=864074 for details.) PowerDevil::Core::onResumeFromSuspend used to (optionally) lock the screen but this changed in a3b0089130145ad15173d1c14ab8a672b93aea65 - now the call is useless at best.
Set powerbutton to turn off screen and tested that it works.