SSL: detect "listen ... ssl" without certificates (ticket #178). In mail and stream modules, no certificate provided is a fatal condition, much like with the "ssl" and "starttls" directives. In http, "listen ... ssl" can be used in a non-default server without certificates as long as there is a certificate in the default one, so missing certificate is only fatal for default servers.

--- a/src/http/ngx_http_core_module.h
+++ b/src/http/ngx_http_core_module.h
@@ -184,6 +184,9 @@ typedef struct {
     /* server ctx */
     ngx_http_conf_ctx_t        *ctx;
 
+    u_char                     *file_name;
+    ngx_uint_t                  line;
+
     ngx_str_t                   server_name;
 
     size_t                      connection_pool_size;