added a hack to create a cli.HelpPrinter if it is nil. Fixes crash when command doesn't exist.
added a hack to create a cli.HelpPrinter if it is nil.
Fixes crash when command doesn't exist.

keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client