skeleton: Remove ftp user and /home/ftp

Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Reviewed-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

system/skeleton/etc/group

@@ -21,6 +21,5 @@ plugdev:x:46:
 staff:x:50:
 lock:x:54:
 netdev:x:82:
-ftp:x:83:
 nogroup:x:99:
 users:x:100:

system/skeleton/etc/passwd

@@ -6,5 +6,4 @@ sync:x:4:100:sync:/bin:/bin/sync
 mail:x:8:8:mail:/var/spool/mail:/bin/false
 www-data:x:33:33:www-data:/var/www:/bin/false
 operator:x:37:37:Operator:/var:/bin/false
-ftp:x:83:83:ftp:/home/ftp:/bin/false
 nobody:x:99:99:nobody:/home:/bin/false