The previous check for an interface operstate only looked for the
literal "UP" in caps, but in my environments I'm seeing operstate
returned as "up" in lower-case, which causes the _is_active_nic
check to fail incorrectly. Example:
[root@overcloud-controller-0 heat-admin]# cat /sys/class/net/eth0/operstate
up
In this environment os-net-config is failing with the exception
in the linked bug.
Change-Id: I85c2d074ce43673c691523ca146ff7cdfdf1c7ca
Closes-Bug: 1569403
2af4ee4b87