IPv6 create-global-addresses does not bite on bridges

[troglobit]

Current Behavior

When creating a bridge interface (likely the same for veth and other non-physical interfaces) the sysctl code to set autoconf=1 runs before the ip link script to create the interface.

Expected Behavior

To enable proper autoconf with global prefix support for IPv6.

Steps To Reproduce

Create a bridge and enable:

admin@switch-00-00-00:/config/interface/br0/ipv6/autoconf/> set create-global-addresses

Then issue leave and exit to the shell:

$ sysctl net.ipv6.conf.br0.autoconf
net.ipv6.conf.br0.autoconf = 0

Additional information

This was supposedly fixed in #136 but did not get tested properly.