Add query for libvirt socket connection refused bug 1251521

Surprised we don't have a query for this fingerprint yet, but it doesn't
show up all that often, but it is still showing up and has a unique
fingerprint compared to some of the other libvirt connection related
bugs that we already know about.

Related-Bug: #1251521

Change-Id: I99fad4a023b834c055862152dbf725adc38fea3d
Merge "Add query for libvirt socket connection refused bug 1251521"