Network access from tasks is now disabled by default. This means that
tasks accessing the network need to be marked as such with the network
flag.

The same marking is also required for the tasks used sudo.

Signed-off-by: Anton Mikanovich <amikan@ilbers.de>

I still don't have final decision on how to deal with privileged tasks.
On the one hand reverting CLONE_NEWUSER flag will allow more smooth downstream
migration. On the other hand marking sudo tasks can be helpfull if we are
going to get rid of sudo soon.
So this moment definitely need some additional discussion.