Parameterize default VRIDs for HA VRRP

HA installs configure two VRRP routers, one for swift and one for the
controller services. Currently these routers are created with hard-coded
VRIDs. Parameterize the VRIDs used to allow for conflicts with existing
VRRP groups or other complex scenarios.

Partial-Bug: #1280277
Merge pull request #14 from CiscoSystems/bugs/1280277

Parameterize default VRIDs for HA VRRP