make glance driver support image:tag

two options:

1/ When the user uploads a docker image to glance, the image must be named in the way of 'image:tag', that means, the 'image:tag' is a image name.

2/ When the user uploads docker image to glance, the image needs to set the tags parameter.
   eg. 'glance image-create --tags tag:test --file ubuntu.tar --name ubuntu --disk-format qcow2 --container-format docker --progress'

Currently implementing the second scheme

Gerrit topic: https://review.openstack.org/#q,topic:bp/is,n,z

Addressed by: https://review.openstack.org/551199
    make glance driver support image:tag

Gerrit topic: https://review.openstack.org/#q,topic:bp/glance-support-tag,n,z

Addressed by: https://review.openstack.org/555650
    make glance driver support tag 'latest'

(hongbin 2018-03-29): It looks all the patches are merged. Could I mark this BP as 'implemented'?

(jiwei 2018-03-30) to hongbin, yes, it is already done. Please set this bp to 'implemented', thanks.