nginx: backport master changes to 19.07

Currently luci is broken in 19.07.
Changes done to fix this problem didn't merge in the
19.07 release.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>

net/nginx/Config_ssl.in

@@ -15,6 +15,13 @@ config NGINX_DAV
 		Enable the HTTP and WebDAV methods PUT, DELETE, MKCOL, COPY and MOVE.
 	default n
 
+config NGINX_UBUS
+	bool
+	prompt "Enable UBUS module"
+	help
+		Enable UBUS api support directly from the server.
+	default y
+
 config NGINX_FLV
 	bool
 	prompt "Enable FLV module"