staging: lustre: fix spelling mistake, "grranted" -> "granted"

Trivial fix to spelling mistake in CERROR error message. Also
clean up the grammar.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>