OpenStack: Allow to provide both tenant name and id

When sourcing an OpenStack rc file, both variables OS_TENANT_ID
and OS_TENANT_NAME are defined.

Signed-off-by: Vincent Giersch <vincent.giersch@ovh.net>
OpenStack: Switch some Info log to Debug

Allow to use $(machine url) without having to pipe the
result due to too verbose Info logs.

Signed-off-by: Vincent Giersch <vincent.giersch@ovh.net>
OpenStack: Allow docker client public key

Signed-off-by: Vincent Giersch <vincent.giersch@ovh.net>
OpenStack: Add inputs flavor, image and network by name

Added parameters:
    --openstack-image-name
    --openstack-flavor-name
    --openstack-net-name

Signed-off-by: Vincent Giersch <vincent.giersch@ovh.net>
Merge pull request #1 from gierschv/openstack-driver

Openstack driver bugfixes and enhancements