Trivial fix to spelling mistake in error messages.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Markus Elfring <elfring@users.sourceforge.net>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>