There is a small issue during changing branch from current to Mitaka, where
there was module called rpc.py, and currently there is a package rpc. Problem
is, if Mistral from master was already at least run once, and changed back to
Mitaka, there is a chance, that directory rpc still exists, and contains pyc
files. Trying to use old rpc module will fail with unable to find
get_transport method due remains of bytecode from master branch.
Simple solution for this situation is to rename rpc module to rpc_backend.
Change-Id: Ib5d05930a9715caf2bb5ce1dba4e520a503bc0cd
606059add8