Change dhparams check to script, correct check.

files/dhparams.sh

+#!/bin/sh -e
+if [ -f /etc/ssl/dhparams.pem ]
+then
+    openssl dhparam -in /etc/ssl/dhparams.pem -text -noout | sed -n 's/Diffie-Hellman-Parameters: (\([0-9]*\) bit)/\1/p'
+else
+    echo 0
+fi