modules/md/md_acme_acct.c (find_acct): Do not dereference a NULL md in the debug log

[PavlNekrasov]

Fix: DEREF_AFTER_NULL

Problem:
find_acct() accepts a candidate account when ctx->md is NULL, and dereferences ctx->md in the very next statement to log it. The two lines contradict each other, so the NULL that the condition admits crashes the logging call.

httpd/modules/md/md_acme_acct.c

Lines 283 to 287 in ba3d76a

	if (MD_ACME_ACCT_ST_VALID == acct->status
	&& (!ctx->md || md_acme_acct_matches_md(acct, ctx->md))) {
	md_log_perror(MD_LOG_MARK, MD_LOG_DEBUG, 0, ctx->p,
	"found account %s for %s: %s, status=%d",
	acct->id, ctx->md->ca_effective, aspect, acct->status);

Solution:
Log the CA only when there is an md, keeping the NULL that the condition already allows.

Signed-off-by: p.nekrasov@fobos-nt.ru
Signed-off-by: sovtouch@altlinux.org

[notroj]

LGTM, thanks.