test: Require pmlogger to actually start in TestHistoryMetrics
test: Require pmlogger to actually start in TestHistoryMetrics

"activating" is not good enough, as it hides bugs like
https://bugzilla.redhat.com/show_bug.cgi?id=2013937 and will just cause
failures later on, which are then (harder to debug and to match with
naughty patterns.

mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,martinpitt/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit