Fix for unexpected entries in /sys/class/net
Fix for unexpected entries in /sys/class/net

For example, in a bonding configuration there is a file there, not just
directories with ifindex entries.

xcat2/confluent,jjohnson42/confluent,whowutwut/confluent,jjohnson42/confluent,jjohnson42/confluent,whowutwut/confluent,jjohnson42/confluent,jjohnson42/confluent,xcat2/confluent,xcat2/confluent,xcat2/confluent,xcat2/confluent,whowutwut/confluent,whowutwut/confluent