Endpoint validation was two-fold - first validation_connection_method
was invoked, and then get for keepalive section, if configured.
This change suggest to run only one validation, but makes sure one
is always run:
if keepalive section is configured, validation will be based on it,
otherwise default validation (validation_connection_method) is used.
For policy, suggested default validation is via infra API.
Change-Id: Ib53d09ba6b2d70f99d5dba781950975c3d7195b6
dafcf8f9bd