nova-manage stack traces when wrong number of arguments are passed

Nova manage shouldn't stack trace when the wrong number of arguments are passed in.

From devstack:

$ nova-manage flavor
/usr/local/bin/nova-manage category action [<args>]
Available actions for flavor category:
        create
        delete
        list
        set_key
        unset_key
vagrant@precise64:~$ nova-manage flavor create
Possible wrong number of arguments supplied
Creates instance types / flavors
Usage: nova-manage flavor create <args> [options]

Options:
  -h, --help show this help message and exit
  --name=<name> Name of instance type/flavor
  --memory=<memory size>
                        Memory size
  --cpu=<num cores> Number cpus
  --root_gb=<root_gb> Root disk size
  --ephemeral_gb=<ephemeral_gb>
                        Ephemeral disk size
  --flavor=<flavor id>
                        Flavor ID
  --swap=<swap> Swap
  --rxtx_factor=<rxtx_factor>
                        rxtx_factor
  --is_public=<is_public>
                        Make flavor accessible to the public
2012-11-26 19:14:13 CRITICAL nova [-] create() takes at least 5 arguments (1 given)
2012-11-26 19:14:13 TRACE nova Traceback (most recent call last):
2012-11-26 19:14:13 TRACE nova File "/usr/local/bin/nova-manage", line 7, in <module>
2012-11-26 19:14:13 TRACE nova execfile(__file__)
2012-11-26 19:14:13 TRACE nova File "/opt/stack/nova/bin/nova-manage", line 1177, in <module>
2012-11-26 19:14:13 TRACE nova main()
2012-11-26 19:14:13 TRACE nova File "/opt/stack/nova/bin/nova-manage", line 1164, in main
2012-11-26 19:14:13 TRACE nova fn(*fn_args, **fn_kwargs)
2012-11-26 19:14:13 TRACE nova TypeError: create() takes at least 5 arguments (1 given)
2012-11-26 19:14:13 TRACE nova