DHC-1456 Update Akanda/Neutron plugins for Havana

DHC-1456

In order to make the RUG working with havana, we need to change
all the references from quantum to neutron

Change-Id: Ieb9f4aea09af2998d921d58dffccc3f0af4ba6a2
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>