Avoid pm-is-supported spam in logs

Per the libvirt team, the only way to stop the spam in
libvirtd logs is to install pm-utils package. Details are in:

https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/994476

Closes-Bug: #1274772
Closes-Bug: #1297512

Change-Id: Ia2f7a388470dcd8a3e2c12cf2980beccd65af94c
Merge "Avoid pm-is-supported spam in logs"