Remove deprecated "ssl" directive from nginx configuration

roles/matrix-server/templates/nginx-conf.d/matrix-riot-web.conf.j2

@@ -33,7 +33,6 @@ server {
 	server_tokens off;
 	root /dev/null;
 
-	ssl on;
 	ssl_certificate {{ matrix_ssl_certs_path }}/live/{{ hostname_riot }}/fullchain;
 	ssl_certificate_key {{ matrix_ssl_certs_path }}/live/{{ hostname_riot }}/privkey;
 	ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

roles/matrix-server/templates/nginx-conf.d/matrix-synapse.conf.j2

@@ -33,7 +33,6 @@ server {
 	server_tokens off;
 	root /dev/null;
 
-	ssl on;
 	ssl_certificate {{ matrix_ssl_certs_path }}/live/{{ hostname_matrix }}/fullchain;
 	ssl_certificate_key {{ matrix_ssl_certs_path }}/live/{{ hostname_matrix }}/privkey;
 	ssl_protocols TLSv1 TLSv1.1 TLSv1.2;