When the k8s cluster is created in a private network without
FIP and without a LB FIP, the cluster is not reachable by Magnum
control plane. For this case, the cluster health status is unknown
for Magnum and Magnum should not connect the cluster to avoid
unnecessary logs.
Task: 36187
Story: 2006383
(cherry picked from commit 177d674e5d9bd5ef745da9b935fc74d8c0b994b8)
Change-Id: Ibb589ec51f91f05a334c907560ef5fe57cbfbffb