Remove cert 1.X rpc api

A previous change adding support for the 2.x rpc interface but retained
compatibility with 1.x as a transition point.  This commit removes the
old API from the server side.

UpgradeImpact

Part of blueprint rpc-major-version-updates-icehouse

Change-Id: I0a5d14fc3cbf374744049269883fc14a4850f597
Merge "Remove cert 1.X rpc api"