Add command information to cinder-manage.rst
Cinder has a command that "cinder-manage backup update_backup_host",
but cinder-manager.rst has no its information. Therefore, I add it.
@@ -126,6 +126,10 @@ Cinder Backup
Displays a list of all backups (including ones in progress) and the host on which the backup operation is running.
+``cinder-manage backup update_backup_host --currenthost <current host> --newhost <new host>``
+
+ Updates the host name of all backups currently associated with a specified host.
+
Cinder Version
~~~~~~~~~~~~~~
