niacctbase: add openvpn user to network group
niacctbase: add openvpn user to network group

Also make sure the group is created before adding to it by
explicitely declaring it. We need this to fix openvpn accessing
/sbin/ip which will be also added to the network group.

Signed-off-by: Ioan-Adrian Ratiu <7ec73abcfe099fc5574c01312b62768070c80980@ni.com>

ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt