cloud-init should include iproute2 output (with MTU) in output

This bug was originally filed in Launchpad as [LP: #1717470](https://bugs.launchpad.net/cloud-init/+bug/1717470)

Launchpad details

affected_projects = []

assignee = None

assignee_name = None

date_closed = None

date_created = 2017-09-15T09:01:21.100018+00:00

date_fix_committed = None

date_fix_released = None

id = 1717470

importance = low

is_complete = False

lp_url = https://bugs.launchpad.net/cloud-init/+bug/1717470

milestone = None

owner = xnox

owner_name = Dimitri John Ledkov

private = False

status = triaged

submitter = xnox

submitter_name = Dimitri John Ledkov

tags = ['nplanfail']

duplicates = []

_Launchpad user **Dimitri John Ledkov(xnox)** wrote on 2017-09-15T09:01:21.100018+00:00_

cloud-init should show output of $ ip address which includes mtu in the console.log