network/test_net: add functions to manage IP addresses

* tst_init_iface() cleanup test interface
* tst_add_ipaddr() add default IPv4 or IPv6 address
* tst_restore_ipaddr() cleanup interface, then
  add default IPv4 and Ipv6 addresses

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
1 file changed