Bug 2233 - RPC register exception when rpc has no input

* added check that should prevent non routed Rpcs being treated as
routed and and failing at context resolution.

Change-Id: I281152879429f2020f48894753f1d57aea85bde6
Signed-off-by: Jan Hajnar <jhajnar@cisco.com>
(cherry picked from commit 170bc1beb43f8082570d066afe6dbd2bf5c3735e)
Merge "Bug 2233 - RPC register exception when rpc has no input" into stable/helium