Remove deprecated agreement url.

"nice" deraadt@
OK benno

src/etc/acme-client.conf

@@ -1,14 +1,12 @@
 #
-# $OpenBSD: acme-client.conf,v 1.5 2017/11/15 12:22:45 florian Exp $
+# $OpenBSD: acme-client.conf,v 1.6 2017/11/27 01:59:55 florian Exp $
 #
 authority letsencrypt {
-        agreement url "https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf"
         api url "https://acme-v01.api.letsencrypt.org/directory"
         account key "/etc/acme/letsencrypt-privkey.pem"
 }
 
 authority letsencrypt-staging {
-        agreement url "https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf"
         api url "https://acme-staging.api.letsencrypt.org/directory"
         account key "/etc/acme/letsencrypt-staging-privkey.pem"
 }