KUDU-2540: Authorization failures on exactly-once RPCs cause FATAL

See the associated JIRA for bug details. The fix follows a slightly
different approach than suggested by Todd, namely initialization of the
RPC tracker in the RPC context is delayed until after authorization.
This allows the error path code to remain unchanged, and allows the one
caller of the RpcContext constructor to be slightly cleaned up.

Change-Id: I9717d36e438bbe68172fa2619c9829ad5fdc779d
Reviewed-on: http://gerrit.cloudera.org:8080/11216
Reviewed-by: Alexey Serbin <aserbin@cloudera.com>
Tested-by: Kudu Jenkins
Reviewed-on: http://gerrit.cloudera.org:8080/11220
Reviewed-by: Adar Dembo <adar@cloudera.com>
4 files changed