Rename quantum repos to neutron

Only the repos are renamed.  This will coincide with the repo rename
operation on July 6.

See https://wiki.openstack.org/wiki/Network/neutron-renaming

Change-Id: I99fe1f80ffc7a54b958b709495b90f8d94d41376
Merge branch 'master' of github.com:openstack-dev/devstack