libsmack: fix smack_new_label_from_path() (regression in e6890752)

Function smack_new_label_from_path failed to null-terminate xattr value
before passing it to get_label.

Signed-off-by: Rafal Krypa <r.krypa@samsung.com>
utils: add options for version and usage information

Added option -v/--version for displaying version information
and -h/--help for displaying usage information.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Merge remote-tracking branch 'rafal-krypa/issue108' into v1.0.x