chsmack: put usage string at head
chsmack: put usage string at head

Setting it at head is a reading improvement for
developpers that can quickly show the usage of the
program. It also makes the main function more readable.

Signed-off-by: José Bollo <08496fd66cc394b517cafa0b18bcb9ce79fe4230@open.eurogiciel.org>

jobol/smack,smack-team/smack,smack-team/smack,jobol/smack