cc-power-panel: hide automatic suspend row in vm
As described in #2521 (closed), the automatic suspend row is currently shown when Settings is running in a VM, in which case it has no effect.
This commit checks whether Settings is running in a VM and disables showing the automatic suspend row in this case, as is done for the Suspend/Hibernate rows. This prevents the user from being shown a useless row in the power panel.
Closes #2521 (closed)