don't segfault on stat-failed

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-merge-1.4.x@552 152afb58-edef-0310-8abb-c4023f1b3aa9

src/mod_compress.c

@@ -86,6 +86,8 @@ FREE_FUNC(mod_compress_free) {
 		size_t i;
 		for (i = 0; i < srv->config_context->used; i++) {
 			plugin_config *s = p->config_storage[i];
+
+			if (!s) continue;
 			
 			array_free(s->compress);
 			buffer_free(s->compress_cache_dir);