When Pod state changes rapidly, endpoints controller may use outdated
informer cache to sync Service. If the outdated endpoints appear to be
expected by the controller, it skips updating it.
The commit fixes it by checking if endpoints informer cache is outdated
when processing a service. If the endpoints is stale, it returns an
error and retries later.
Signed-off-by: Quan Tian <quan.tian@broadcom.com>
