Fixed inconsistent positional arguments naming
Fixed inconsistent positional arguments naming

When printing the help menu for Swift commands, it is confusing to see
both positional arguments and options not distinguished. The
positional arguments are supposed to be enclosed in angular braces <>,
options in square braces [] and optional positional arguments in [<>].

Change-Id: Ie84a90eb0278dd2cdf5775948572bb140f8d2c4b

sohonetlabs/python-swiftclient,sohonetlabs/python-swiftclient,openstack/python-swiftclient,openstack/python-swiftclient