Fixed error reporting

Removed redundant print line and fixed handling of command-less docker
invocation.

Signed-off-by: Michal Minar <miminar@redhat.com>

api/client/commands.go

@@ -63,7 +63,6 @@ func (cli *DockerCli) CmdHelp(args ...string) error {
 	if len(args) > 0 {
 		method, exists := cli.getMethod(args[0])
 		if !exists {
-			fmt.Fprintf(cli.err, "Error: Command not found: %s\n", args[0])
 			fmt.Fprintf(cli.err, "docker: '%s' is not a docker command. See 'docker --help'.\n", args[0])
 			os.Exit(1)
 		} else {