Inconsistent parsing of boolean flags between parent and child commands

[parametalol]

Expected behavior: command flags should be allowed in front of the commands, even without =true.
Actual behavior: persistent boolean flags put in front of the command are not recognized.

func Test_flagsOrder(t *testing.T) {
	rootCommand := &cobra.Command{SilenceUsage: true, Args: cobra.MaximumNArgs(0)}
	var flagValue bool
	rootCommand.PersistentFlags().BoolVar(&flagValue, "rootflag", false, "root boolean flag")

	cmd := &cobra.Command{Use: "command", SilenceUsage: true, Args: cobra.MaximumNArgs(0)}
	cmd.PersistentFlags().BoolVar(&flagValue, "cmdflag", false, "command boolean flag")
	rootCommand.AddCommand(cmd)

	for name, args := range map[string][]string{
		"root flag before command":                {"--rootflag", "command"},     // ok
		"command flag before command":             {"--cmdflag", "command"},      // unknown flag: --cmdflag
		"command flag with =value before command": {"--cmdflag=true", "command"}, // ok
	} {
		t.Run(name, func(t *testing.T) {
			flagValue = false
			rootCommand.SetArgs(args)
			if err := rootCommand.Execute(); err != nil {
				t.Error(err)
			}
			if !flagValue {
				t.Errorf("flag is false")
			}
		})
	}
}

Output:

-- FAIL: Test_flagsOrder (0.00s)
    --- FAIL: Test_flagsOrder/command_flag_before_command (0.00s)
        flags_test.go:27: unknown flag: --cmdflag
        flags_test.go:30: flag is false

Moved here from spf13/pflag#421