as long as the target is not in inventory

[richardtief]

Example error from vrops-exporter-vrops-vc-b-0-host

Traceback (most recent call last):
  File "/usr/lib/python3.8/wsgiref/handlers.py", line 137, in run
    self.result = application(self.environ, self.start_response)
  File "/usr/lib/python3.8/site-packages/prometheus_client/exposition.py", line 52, in prometheus_app
    status, header, output = _bake_output(registry, accept_header, params)
  File "/usr/lib/python3.8/site-packages/prometheus_client/exposition.py", line 40, in _bake_output
    output = encoder(registry)
  File "/usr/lib/python3.8/site-packages/prometheus_client/openmetrics/exposition.py", line 14, in generate_latest
    for metric in registry.collect():
  File "/usr/lib/python3.8/site-packages/prometheus_client/registry.py", line 82, in collect
    for metric in collector.collect():
  File "/vrops-exporter/collectors/HostSystemStatsCollector.py", line 24, in collect
    token = token[self.target]
AttributeError: 'HostSystemStatsCollector' object has no attribute 'target'