[VPP-2124] IPv6 Ready 1.2.9 - handling of RH with segments left == 0

### Description
IPv6 Ready compliance tests 1.2.9 and RFC8200 requires that any RH with segments left == 0 must be processed/skipped by host processing.


Current VPP implementation drops it as unknown protocol.

### Assignee
Unassigned

### Reporter
Ole Trøan

### Comments
No comments.

Original issue: https://jira.fd.io/browse/VPP-2124