Add accidentally deleted test_hooks.py
Add accidentally deleted test_hooks.py

In patch https://review.openstack.org/#/c/258485/11, test_hooks.py
was deleted accidentally. So this patch adds the file.

Change-Id: I9ce4636f20e9a9a4c7b4f5a7037267c2dd4097a9

openstack/magnum,ArchiFleKs/magnum,openstack/magnum,ArchiFleKs/magnum