Merge pull request #2701 from elfiesmelfie/feat_virt_notify_lifecycle

virt: Fix tracking of VM state changes

diff --cc Makefile.am
Simple merge

diff --cc src/collectd.conf.in
Simple merge

diff --cc src/collectd.conf.pod
Simple merge

diff --cc src/daemon/plugin_mock.c
Simple merge

diff --cc src/virt.c
Simple merge