Add note for wiki and correct Arch Linux
Merge pull request #488 from svenstaro/patch-1

Add note for wiki and correct Arch Linux
use of DSA keys can lead to a crash at startup, the crash is caused
by a use-after-free. spotted by millert, fix by deraadt
Merge branch 'master' of https://github.com/OpenSMTPD/OpenSMTPD
Merge branch 'master' into portable