Added the import of lib/infra

This fixes an error in the devstack/functions
setup_develop call, which tries to cd to
$REQUIREMENTS_DIR, which is created in lib/infra

Change-Id: Ie65d2ba83547acc4ea36d1191e6e90dc21da1fa7
Closes-Bug: #1276365
Set DEFAULT_IMAGE_NAME for Docker hypervisor

This allows the tempest configuration to set the right
image for booting docker containers with Nova.

Since glance uploads are not yet integrated in devstack,
IMAGE_URLS remains empty.

Change-Id: I5df153cd1d5e1411bb3c11816122ce280148e129
Merge "Added the import of lib/infra"
Merge "Set DEFAULT_IMAGE_NAME for Docker hypervisor"
Merge branch 'master' of https://github.com/openstack-dev/devstack