ovn-k8s-overlay: Flush IP address and routes of internal interface.
ovn-k8s-overlay: Flush IP address and routes of internal interface.

When the same 'master-init' command is run multiple times on the same
host, you get warnings relating to existing routes and addresses.
Flusing before setting them helps us get rid of these warnings

Signed-off-by: Gurucharan Shetty <a1872e333d0e52644f6125da2276530f7ebe5e77@ovn.org>

shettyg/ovn-kubernetes,shettyg/ovn-kubernetes,shettyg/ovn-kubernetes