Docker 1.11.0 fails to activate libnetwork plugins specified with .json files.
Using .spec files still works. Adding a .spec file and configuring devstack to
work around the bug.
Change-Id: I041a5e9a526c2e63c92f3d01411afda8b7beb601
Closes-Bug: #1572369
Signed-off-by: Frederick F. Kautz IV <fkautz@redhat.com>