libxt_comment: silence truncation warning

gcc warned here:
libxt_comment.c:62 output may be truncated before the last format character [-Wformat-truncation=]
snprintf(comment, XT_MAX_COMMENT_LEN, "\"%s\"" ...

It tells us that the '"' might not fit anymore, so increase output
buffer size to make room for "" escapes too.

Signed-off-by: Florian Westphal <fw@strlen.de>
1 file changed