interfaces: T4331: Fix assign link-local static IPv6 addr to vrf

[sever-sever]

Change Summary

Set address after vrf
Fix assign link-local static address to vrf

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://phabricator.vyos.net/T4331

Component(s) name

interfaces

Proposed changes

How to test

If we have link-local static address fe80::5200:ff:fe55:222/64 and vrf, for example:

set interfaces ethernet eth2 address 'fe80::5200:ff:fe55:222/64'
set interfaces ethernet eth2 vrf 'foo'

This IPv6 address was assign before vrf, as result after
attaching the interface to vrf we lose this static linklocal
address

DEBUG/IFCONFIG cmd 'ip addr add fe80::5200:ff:fe55:222/64 dev eth2'
DEBUG/IFCONFIG cmd 'ip link set dev eth2 master foo'
DEBUG/IFCONFIG cmd 'ip addr add fe80::5208:ff:fe13:2/64 dev eth2'

Before fix IPv6 address fe80::5200:ff:fe55:222/64 not in the routing table:

set interfaces ethernet eth2 address 'fe80::5200:ff:fe55:222/64'
set interfaces ethernet eth2 address '192.0.2.5/32'
set interfaces ethernet eth2 address '2002:2::2/120'
et interfaces ethernet eth2 vrf 'foo'
set vrf name foo table '120'

4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master foo state UP group default qlen 1000
    link/ether 50:08:00:13:00:02 brd ff:ff:ff:ff:ff:ff
    inet 192.0.2.5/32 scope global eth2
       valid_lft forever preferred_lft forever
    inet6 2002:2::2/120 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::5208:ff:fe13:2/64 scope link 
       valid_lft forever preferred_lft forever

After fix IPv6 address fe80::5200:ff:fe55:222/64 in the routing table

4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master foo state UP group default qlen 1000
    link/ether 50:08:00:13:00:02 brd ff:ff:ff:ff:ff:ff
    inet 192.0.2.5/32 scope global eth2
       valid_lft forever preferred_lft forever
    inet6 2002:2::2/120 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::5208:ff:fe13:2/64 scope link 
       valid_lft forever preferred_lft forever
    inet6 fe80::5200:ff:fe55:222/64 scope link 
       valid_lft forever preferred_lft forever

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly