Configure kingpin to stop thinking args for command belong to it

Fix the annoying behavior where flags passed as part of command were
being sucked in by kingpin and throwing errors about undefined flags.
That required users to explicitly put `--` between the profile and command.

This fixes that behavior so kingpin only handles its own flags, and leaves
flags for cmd alone, and passed thru

Author: Mike Morris

main.go

@@ -182,6 +182,10 @@ func getAWSSession() *session.Session {
 }
 
 func main() {
+	// Tell kingpin to stop parsing flags once we start processing 'cmd', allows something like:
+	// `aws-runas --verbose profile command -a --long_arg`
+	// without needing an explicit `--` between 'profile' and 'cmd'
+	kingpin.CommandLine.Interspersed(false)
 	kingpin.Parse()
 
 	if *verbose {