Create directory for dhp-4096.pem

Author: ffdixon

_posts/2019-02-15-install.md

@@ -666,6 +666,7 @@ END</code></pre>
 In addition, we'll generate a set of 4096-bit diffie-hellman parameters to improve security for some types of ciphers. This step can take several minutes to complete, particularly if run on a virtual machine.
 
 ```bash
+sudo mkdir -p /etc/nginx/ssl
 sudo openssl dhparam -out /etc/nginx/ssl/dhp-4096.pem 4096
 ```
 
@@ -804,6 +805,7 @@ $ sudo apt-get install certbot
 Next, generate a set of 4096-bit diffie-hellman parameters to improve security for some types of ciphers.
 
 ```bash
+sudo mkdir -p /etc/nginx/ssl
 sudo openssl dhparam -out /etc/nginx/ssl/dhp-4096.pem 4096
 ```