Fix a parsing issue with command line arguments

Prior to now, helm has been silently ignoring any errors while parsing
the root Persistent flags. This causes an issue when a global flag comes
later on the command line than a localized flag for a subcommand, in
which the value for that global flag is never set. The solution is to
simply tell the Persistent flagset to ignore any unknown flags, since a
later command will process it

Signed-off-by: Ian Howell <ian.howell0@gmail.com>

cmd/helm/root.go

@@ -119,6 +119,11 @@ func newRootCmd(actionConfig *action.Configuration, out io.Writer, args []string
 
 	settings.AddFlags(flags)
 
+	// We can safely ignore any errors that flags.Parse encounters since
+	// those errors will be caught later during the call to cmd.Execution.
+	// This call is required to gather configuration information prior to
+	// execution.
+	flags.ParseErrorsWhitelist.UnknownFlags = true
 	flags.Parse(args)
 
 	// set defaults from environment