add additional includes required to build with -DOPENSSL_NO_DEPRECATED

from jsg@

Conflicts:
	smtpd/ca.c
	smtpd/ssl.c
memset buffer before using it

by Martijn van Duren
use errx() not err() otherwise the error message will be bogus
Merge branch 'master' of ssh://ssh.github.com/OpenSMTPD/OpenSMTPD