Correct the swift tempurl arguments help message

[YangLei]

[method]
[seconds]
[path]
[key]
should be
<method>
<seconds>
<path>
<key>

in Positional arguments.

st_tempurl_options = '<method> <seconds> <path> <key>'

st_tempurl_help = '''
Generates a temporary URL for a Swift object.

Positional arguments:
  [method] An HTTP method to allow for this temporary URL.
                        Usually 'GET' or 'PUT'.
  [seconds] The amount of time in seconds the temporary URL will
                        be valid for.
  [path] The full path to the Swift object. Example:
                        /v1/AUTH_account/c/o.
  [key] The secret temporary URL key set on the Swift cluster.
                        To set a key, run \'swift post -m
                        "Temp-URL-Key:b3968d0207b54ece87cccc06515a89d4"\'
'''.strip('\n')

[John Dickinson (notmyname)]

fixed in https://review.openstack.org/#/c/196970/