nova-status was missing in the list of man-pages. So when building the
man-pages with:
sphinx-build -b man doc/source doc/build/man
there is no "nova-status" in doc/build/man.
Also sort the list alphabetically so it's easier to parse for humans.
Closes-Bug: 1843714
Change-Id: I20b73d508bc6341195c991111ac84c3e35905c92