Update the wsk command output.

[lzbj]

As OpenWhisk switch from python cli to go cli, we need to update the wsk --help command out put to reflect this change.

Here the latest go-cli output with the command:
wsk --help

    ____      ___                   _    _ _     _     _
   /\   \    / _ \ _ __   ___ _ __ | |  | | |__ (_)___| | __

/\ /\ \ | | | | '_ \ / _ \ '_ | | | | '_ | / | |/ /
/ * \ / | || | |) | / | | | |/| | | | | * \ <
\ \ / / _/| ./ _|| ||/__|| ||_|/|_
**/ tm ||

Usage:
wsk [command]

Available Commands:
action work with actions
activation work with activations
package work with packages
rule work with rules
trigger work with triggers
sdk work with the sdk
property work with whisk properties
namespace work with namespaces
list list available namespaces

Flags:
--apihost HOST whisk API HOST
--apiversion VERSION whisk API VERSION
-u, --auth KEY authorization KEY
-d, --debug debug level output
-i, --insecure bypass certificate checking
-v, --verbose verbose output

Use "wsk [command] --help" for more information about a command.

[lzbj]

More detailed updates:
apache/openwhisk#934