Fix 'icehouse-compat' processing for compute rpc

Commit 2c63cae921d024f39f7d14459873d20caa5cf9e0 added some havana
specific rpc handling to aid with the live upgrade from havana to
icehouse.  Unfortunately, the processing was broken for some
methods.  It would claim to be sending a '3.0' message, but would
be sending some of the arguments in an old format, causing some
methods to break when processed on the remote end.

This patch fixes up the logic to ensure that if messages are sent as
'3.0', that the format of the data sent in the message matches.

Note that this is a stable/havana specific change.

Change-Id: I54135effe4e083f73cb7d912ac9e82fd182e2b2d
Closes-bug: #1301436