Fix configure the network adapter section in docs

Targeted for stable/4.0

Closes-bug: #1279221

Change-Id: Ie3aea7b855db1c7f0f997e53860ebe1e36aaf02d
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Merge "Fix configure the network adapter section in docs"