Sometimes in case of HA routers it may happend that
keepalived will set status of router to MASTER before
neutron-keepalived-state-change daemon will spawn "ip monitor"
to monitor changes of IPs in router's namespace.
In such case neutron-keepalived-state-change process will never
notice that keepalived set router to be MASTER and L3 agent will
not be notified about that so router will not be configured properly.
To avoid such race condition neutron-keepalived-state-change will
now check if VIP address is already configured on ha interface
before it will spawn "ip monitor". If it is already configured
by keepalived, it will notify L3 agent that router is set to
MASTER.
Change-Id: Ie3fe825d65408fc969c478767b411fe0156e9fbc
Closes-Bug: #1818614
(cherry picked from commit 8fec1ffc83)