Use helpers from charmhelpers to generate the data to send down the
relation to the hacluster charm.
This results in a few changes in behaviour:
1) The charm will no longer specify a nic name to bind the vip. This
is because Pacemaker VIP resources are able to automatically
detect and configure correct iface and netmask parameters based
on local configuration of the unit.
2) The original iface named VIP resource will be stopped and deleted
prior to the creation of the new short hash named VIP resource.
Change-Id: Id3804fb7913662b8c573f59d84e663561a687b1f
29b586c61b