Add iptables and listening sockets to debug info

The method "_log_local_network_status", used to print the system
information in case of error, is improved with new information:
- The local namespace iptables
- The local namespace listening sockets

This information could provide the needed info to investigate the
problem, related in the referred bug, when a VM cannot retrieve
the metadata information.

Change-Id: Id56743a07267b4b6c03e7b9b295f919668ac07ab
Related-Bug: #1923633
2 files changed