Description of problem:

Version-Release number of selected component (if applicable):
2.4.0

How reproducible:
100%

Steps to Reproduce:
1. oc adm must-gather \
--image-stream=openshift/must-gather \
--image=registry.redhat.io/container-native-virtualization/cnv-must-gather-rhel8

Actual results:
[must-gather-r9ggf] POD Error from server (NotFound): namespaces "kubevirt-hyperconverged" not found
[must-gather-r9ggf] POD Error from server (NotFound): namespaces "cluster-network-addons" not found
[must-gather-r9ggf] POD Error from server (NotFound): namespaces "openshift-sdn" not found
[must-gather-r9ggf] POD Error from server (NotFound): namespaces "sriov-network-operator" not found
[must-gather-r9ggf] POD Error from server (NotFound): namespaces "kubevirt-web-ui" not found
[must-gather-r9ggf] POD Error from server (NotFound): namespaces "cdi" not found

Expected results:
silence

Additional info:
Upstream code https://github.com/kubevirt/must-gather/blob/master/collection-scripts/gather#L7 refers to downstream and upstream namespaces alike.

Downstream should refer only to expected downstream namespaces. False Errors may mislead customers.