Allow resizes and migrates during live upgrade

This patch completes the changes needed to havana's compute rpc api to
allow live upgrades to icehouse.  Specifically, these changes are needed
to allow resizes and migrates to work.  Before havana compute nodes get
put in a mixed environment with icehouse compute nodes, they need to be
speaking version 3.0 messages.

Change-Id: If09bd38c9d8c3beb5b95107c497699dec47aa3ef
Closes-bug: #1258253
Merge "Allow resizes and migrates during live upgrade" into stable/havana