column: fix outputing empty column at the end of line

column: fix outputing empty column at the end of line

The following commands manifests the problem.  In old versions before
commit 4762ae9d60 ("column: use libsmartcols for --table"), both of them
should output with 2 "|"

	echo '||'  | column -o '|' -s '|' -t
	echo '|| ' | column -o '|' -s '|' -t

Fixes: 4762ae9d60 ("column: use libsmartcols for --table")
Signed-off-by: Yousong Zhou <zhouyousong@yunionyun.com>
Reviewed-by: Sami Kerola <kerolasa@iki.fi>