This change allows using a local directory or tarball to build from
sources by specifying the 'local' type in your kolla-build.conf:

    [keystone-base]
    type=local
    location=/home/martin/src/keystone

    [neutron-server-plugin-networking-cisco]
    type=local
    location=/tmp/networking-cisco.tar.gz

Closes-Bug: #1509625
Co-Authored-By: Martin André <m.andre@redhat.com>
Change-Id: I3f6f68b0f44efdac653d186d2625591ad7cb3b2a