Support shortened versions of cluster-internal service name

[tcnghia]

Expected Behavior

Internal cluster name is supported, including the shortened version.

Actual Behavior

Only the fully qualified domain name is supported.

[tcnghia]

@scothis

[tcnghia]

This may be an issue on Istio side, I'll follow up with them.

[tcnghia]

@ZhiminXiang has seen this working correctly with the latest build so we should try to check again with the Istio 1.0-snapshot version.