cloudinit.net.get_devicelist includes "bonding_masters" if present

This bug was originally filed in Launchpad as [LP: #1917322](https://bugs.launchpad.net/cloud-init/+bug/1917322)

Launchpad details

affected_projects = []

assignee = None

assignee_name = None

date_closed = None

date_created = 2021-03-01T14:44:29.865105+00:00

date_fix_committed = None

date_fix_released = None

id = 1917322

importance = low

is_complete = False

lp_url = https://bugs.launchpad.net/cloud-init/+bug/1917322

milestone = None

owner = oddbloke

owner_name = Dan Watkins

private = False

status = triaged

submitter = oddbloke

submitter_name = Dan Watkins

tags = []

duplicates = []

_Launchpad user **Dan Watkins(oddbloke)** wrote on 2021-03-01T14:44:29.865105+00:00_

$ ls -l /sys/class/net/
total 0
lrwxrwxrwx 1 root root 0 Feb 26 21:51 bond0 -> ../../devices/virtual/net/bond0
-rw-r--r-- 1 root root 4096 Feb 26 21:51 bonding_masters
lrwxrwxrwx 1 root root 0 Feb 26 21:51 enp5s0 -> ../../devices/pci0000:00/0000:00:01.4/0000:05:00.0/virtio12/net/enp5s0
lrwxrwxrwx 1 root root 0 Feb 26 21:51 lo -> ../../devices/virtual/net/lo
lrwxrwxrwx 1 root root 0 Feb 26 21:51 ovs-br -> ../../devices/virtual/net/ovs-br
lrwxrwxrwx 1 root root 0 Feb 26 21:51 ovs-br.100 -> ../../devices/virtual/net/ovs-br.100
lrwxrwxrwx 1 root root 0 Feb 26 21:51 ovs-system -> ../../devices/virtual/net/ovs-system

$ python3 -c "from cloudinit.net import get_devicelist; print(get_devicelist())"
['bonding_masters', 'enp5s0', 'bond0', 'ovs-system', 'ovs-br.100', 'lo', 'ovs-br']