This adds the basic framework for the nova-status
upgrade check commands. Follow up patches will flesh
this out to perform cells v2 and placement API related
upgrade status checks.
A man page is added for the new CLI and as part of that
the man page index is sorted.
Part of blueprint cells-scheduling-interaction
Part of blueprint resource-providers-scheduler-db-filters
Change-Id: I687dd7317703a1bb76c197ebba849ca368c0872e
a1f3a5946a