Check if vpn dhparams get generated

src/freedombone-app-vpn

@@ -549,8 +549,14 @@ function install_vpn {
 
     # generate host keys
     if [ ! -f /etc/openvpn/dh2048.pem ]; then
-        openssl dhparam -out /etc/openvpn/easy-rsa/keys/dh2048.pem 2048
+        openssl dhparam -out /etc/openvpn/dh2048.pem 2048
     fi
+    if [ ! -f /etc/openvpn/dh2048.pem ]; then
+        echo $'vpn dhparams were not generated'
+        exit 73724523
+    fi
+    cp /etc/openvpn/dh2048.pem /etc/openvpn/easy-rsa/keys/dh2048.pem
+
     cd /etc/openvpn/easy-rsa
     . ./vars
     ./clean-all