busybox: disable default config option FEATURE_SUID=y

busybox: disable default config option FEATURE_SUID=y

Commit ad7c6102f209 ("busybox: fix missing install with suid bit set if
FEATURE_SUID=y") actually fixes BUSYBOX_CONFIG_FEATURE_SUID option and
thus would install busybox setuid root by default which would result in
possibly unwanted change of current behaviour, so let's disable this
option by default in order to preserve the current status-quo.

For the record: disabling FEATURE_SUID to preserve the status-quo does
*not* imply the current status-quo is "safer", or for that matter, in
any way desireable.  That is a discussion to be had on the mailing
lists.

Switching the FEATURE_SUID default to "n" is simply a compromise to
facilitate the merge of the changes that unbreak FEATURE_SUID.

Ref: PR#2502
Signed-off-by: Henrique de Moraes Holschuh <henrique@nic.br>
[commit title/description facelift]
Signed-off-by: Petr Štetiar <ynezz@true.cz>