bgpd: VRF-Lite fix to clear stale leaked routes

bgpd: VRF-Lite fix to clear stale leaked routes

Description:
Change is intended for fixing the issue related to
clearing of stale leaked routes:
- Whenever BGP goes down,
  after bringing down tcp connection and renegotiating capabilities,
  once we reestablish connection,
  we are not handling clear of VRF leaked route in the bgp_clear_stale_route.

- While bgp is clearing stale routes,
  we need to handle withdraw of routes for VRF route-leaking.

Co-authored-by: Kantesh Mundaragi <kmundaragi@vmware.com>
Signed-off-by: Iqra Siddiqui <imujeebsiddi@vmware.com>