selftests/utils/test_network is failing when IPv6 is disabled

[beraldoleal]

Describe the bug Depending on the machine, this test is failing because when IPV6 is disabled scoket() or bind() will return an error. Test needs to be refactored.

Steps to reproduce

ip a | grep inet6
$ ipython3
In [1]: import socket                                                                                                  

In [2]: sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)                                                      

In [3]: sock.bind(('localhost', 2121))                                                                                 
---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
<ipython-input-3-9c024125f5f7> in <module>
----> 1 sock.bind(('localhost', 2121))

OSError: [Errno 99] Cannot assign requested address

Expected behavior Test should pass or be skipped.

Current behavior Test is failing

System information (please complete the following information):

• OS:

LSB Version:	:core-4.1-amd64:core-4.1-noarch
Distributor ID:	Fedora
Description:	Fedora release 34 (Thirty Four)
Release:	34
Codename:	ThirtyFour

• Avocado version: master branch
• Avocado installation method: setup.py develop

Additional information Add any other information about the problem here. Test details can be added here.

[clebergnu]

@beraldoleal can you check if this still applies? Thanks.