fix ipv4 replacement of running containers

fix ipv4 replacement of running containers

While the previous strategy was enough for ipv6, ipv4 has
the concept of primary and secondary addresses (and
permanent, deprecated, ...), and so adding additional ip
addresses marked them as 'secondary'. The side effect of
this is that deleting the primary ip deletes all other ip
addresses within the same subnet. To avoid this we need to
temporarily set /proc/sys/net/ipv4/conf/promote_secondaries
to 1 before deleting the old IP address.