[5302] Updated paths to the cert files for nginx.

doc/examples/https/nginx/kea-nginx.conf

@@ -52,11 +52,11 @@ http {
         server_name kea.example.org;
 
         #   Server certificate and key.
-        ssl_certificate kea-proxy.crt;
-        ssl_certificate_key kea-proxy.key;
+        ssl_certificate /path/to/kea-proxy.crt;
+        ssl_certificate_key /path/to/kea-proxy.key;
 
         #   Certificate Authority. Client certificate must be signed by the CA.
-        ssl_client_certificate ca.crt;
+        ssl_client_certificate /path/to/ca.crt;
 
         # Enable verification of the client certificate.
         ssl_verify_client on;