docker plugin add restart policies and capability properties

[LiangChen]

Restart policies and capability features has supported since Docker 1.2, At the same time,
the docker-py project supports them.

I think we should add restart_policy, cap_add and cap_drop properties in the heat-docker
for the stability and security?

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/163277

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/163277
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=7dfc5767360be6df90d1aad3bf8b045cd270d497
Submitter: Jenkins
Branch: master

commit 7dfc5767360be6df90d1aad3bf8b045cd270d497
Author: LiangChen <email address hidden>
Date: Wed Mar 11 12:01:23 2015 +0800

    Docker plugin add restart policies and capability properties

    Add restart_policy, cap_add and cap_drop properties for stability and security.

    Closes-bug: #1430197

    Change-Id: Iec184fdf5c765217ff7058e8b1390b2f73c59b40