container/lxc: Updates setupHostVethDevice to remove old DHCPv6 leases on IP change
container/lxc: Updates setupHostVethDevice to remove old DHCPv6 leases on IP change

When a static IPv6 address is changed on a bridged nic for managed networks the old DHCPv6 leases are cleared.

The host side interface of the veth pair is also bounced to allow the container to detect the change in carrier and re-apply for the lease.

Fixes #5891

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

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