Revert "Update to ChaosVPN 2.18"

This reverts commit f2e04920.

Hangs on start if started from /etc/hostname.if. Weird.

Makefile

 # $OpenBSD$
 
 COMMENT =	configuration manager for the tinc VPN daemon
-VERSION =	2.18
+VERSION =	2.17
 DISTNAME =	chaosvpn-${VERSION}
 REVISION =	0
 CATEGORIES =	net

distinfo

-SHA256 (v2.18.tar.gz) = qiMkvleIHKpZyfBL3A35uUjcOnXSSAeq5izMpJaRtXE=
-SIZE (v2.18.tar.gz) = 91829
+SHA256 (v2.17.tar.gz) = hAwGBlEE6QAxqs1pSCeVBv9U2SIopGnOZIGr8ZI1dBo=
+SIZE (v2.17.tar.gz) = 90471