Actually restart with new code when running the clustered rt client

We need to prevent the coordinator from simply forking off a new copy of the
old code by committing suicide in the recommended cluster way. This causes the
parent to exit when all clients have quit, which in turn leads to a restart
from upstart with new code.

Change-Id: I992bb46c3a001dfe30560d635a0b6a8abd58117c