cmd/root: Work around Cobra 1.1.2's handling of usage functions

In version 1.1.2 of Cobra has been included a change[0] that changes
how custom usage functions are handled.

Example of the wrong behaviour:
$ toolbox --foo
Error: unknown flag: --foo
Run 'toolbox --help' for usage.Error: Run 'toolbox --help' for usage.

Desired behaviour:
$ toolbox --foo
Error: unknown flag: --foo
Run 'toolbox --help' for usage.

A workaround is to define a template string for the usage instead. The
template uses the templating language of Go[1]. See the default
template string in version 1.2.1[2].

Because the template is set only once, the executableBase needs to be
set before the template is applied. That required the move of
setUpGlobals() into init() of the cmd package. This is a better place
for the function call as init() is called earlier than Execute()[3].

Upstream issue: spf13/cobra#1532

[0] spf13/cobra#1044
[1] https://pkg.go.dev/text/template
[2] https://github.com/spf13/cobra/blob/v1.2.1/command.go#L491
[3] https://golang.org/doc/effective_go#init

containers#917

src/cmd/root.go

@@ -62,11 +62,6 @@ var (
 )
 
 func Execute() {
-	if err := setUpGlobals(); err != nil {
-		fmt.Fprintf(os.Stderr, "Error: %s\n", err)
-		os.Exit(1)
-	}
-
 	if err := rootCmd.Execute(); err != nil {
 		os.Exit(1)
 	}
@@ -75,6 +70,11 @@ func Execute() {
 }
 
 func init() {
+	if err := setUpGlobals(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %s\n", err)
+		os.Exit(1)
+	}
+
 	persistentFlags := rootCmd.PersistentFlags()
 
 	persistentFlags.BoolVarP(&rootFlags.assumeYes,
@@ -96,7 +96,9 @@ func init() {
 	persistentFlags.CountVarP(&rootFlags.verbose, "verbose", "v", "Set log-level to 'debug'")
 
 	rootCmd.SetHelpFunc(rootHelp)
-	rootCmd.SetUsageFunc(rootUsage)
+
+	usageTemplate := fmt.Sprintf("Run '%s --help' for usage.", executableBase)
+	rootCmd.SetUsageTemplate(usageTemplate)
 }
 
 func preRun(cmd *cobra.Command, args []string) error {
@@ -188,12 +190,6 @@ func rootRun(cmd *cobra.Command, args []string) error {
 	return rootRunImpl(cmd, args)
 }
 
-func rootUsage(cmd *cobra.Command) error {
-	err := fmt.Errorf("Run '%s --help' for usage.", executableBase)
-	fmt.Fprintf(os.Stderr, "%s", err)
-	return err
-}
-
 func migrate() error {
 	logrus.Debug("Migrating to newer Podman")