Merge pull request #931 from ioannidesalex/patch-9

Dovecot security hardening

install/ubuntu/16.04/dovecot/conf.d/10-ssl.conf

@@ -1,3 +1,5 @@
 ssl = yes
+ssl_protocols = !SSLv2 !SSLv3
+
 ssl_cert = </usr/local/vesta/ssl/certificate.crt
 ssl_key = </usr/local/vesta/ssl/certificate.key