test_net.sh: add tst_wait_ipv6_dad()

New function is waiting for IPv6 DAD completion on the specified
interfaces.

Add it to netns setup to make sure previously configured
IPv6 addresses are ready to be used by tests.

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
1 file changed