Fix for mysterious warning "Could not create directory ." on Hostmaster site Verify.

Provision/Config.php

@@ -185,7 +185,7 @@ class Provision_Config {
   function write() {
     $filename = $this->filename();
     // Make directory structure if it does not exist.
-    if (!provision_file()->exists(dirname($filename))->status()) {
+    if ($filename && !provision_file()->exists(dirname($filename))->status()) {
       provision_file()->mkdir(dirname($filename))
         ->succeed('Created directory @path.')
         ->fail('Could not create directory @path.');