Merge pull request #372 from neuhaus/patch-1

Dovecot: Fix for logjam attack

roles/mailserver/files/etc_dovecot_conf.d_10-ssl.conf

 
 # SSL crypto device to use, for valid values run "openssl engine"
 #ssl_crypto_device =
+
+# DH parameters length to use.
+ssl_dh_parameters_length = 2048