Add nova-status upgrade check command framework

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

requirements.txt

@@ -22,6 +22,7 @@ netaddr!=0.7.16,>=0.7.13 # BSD
 netifaces>=0.10.4 # MIT
 paramiko>=2.0 # LGPLv2.1+
 Babel>=2.3.4 # BSD
+enum34;python_version=='2.7' or python_version=='2.6' or python_version=='3.3'  # BSD
 iso8601>=0.1.11 # MIT
 jsonschema!=2.5.0,<3.0.0,>=2.0.0 # MIT
 python-cinderclient!=1.7.0,!=1.7.1,>=1.6.0 # Apache-2.0

setup.cfg

@@ -67,6 +67,7 @@ console_scripts =
     nova-scheduler = nova.cmd.scheduler:main
     nova-serialproxy = nova.cmd.serialproxy:main
     nova-spicehtml5proxy = nova.cmd.spicehtml5proxy:main
+    nova-status = nova.cmd.status:main
     nova-xvpvncproxy = nova.cmd.xvpvncproxy:main
 wsgi_scripts =
     nova-placement-api = nova.api.openstack.placement.wsgi:init_application