This patch adds an option '-g'/'--global-project' to the 'cluster-list'
command so that an admin user can list clusters from all
tenants/projects.
Change-Id: I9fac64f1e81a6d4e61a93d57a1272d175e8b61e0
Depends-On: Icab38c970de7704c3134afd1b96a03b3670bd2ad