Ignore wifi collector permission errors (#646)
Ignore wifi collector permission errors (#646)

Ignore the permission denined error when the wifi collector has no
permission to read metrics.
Jean-Daniel/node_exporter,derekmarcotte/node_exporter,siavashs/node_exporter,joehandzik/node_exporter,prometheus/node_exporter,prometheus/node_exporter,prometheus/node_exporter,joehandzik/node_exporter,siavashs/node_exporter,siavashs/node_exporter,joehandzik/node_exporter,derekmarcotte/node_exporter,Jean-Daniel/node_exporter,Jean-Daniel/node_exporter,derekmarcotte/node_exporter,derekmarcotte/node_exporter,joehandzik/node_exporter,Jean-Daniel/node_exporter,siavashs/node_exporter