DHC-1174 - As a developer I can install akanda with devstack from trunk

DHC-1174

This is the first step to upgrade our devstack repo(which
include Akanda installation) to Havana.

Change-Id: I3f335dda70ba1ea9e2193af103de47e30a1ccd43
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>