Remote import does not support WP blogs outside site root

Hi.

If a WP blog is found at http://example.com/myblog/, and import is done using credentials (something like example.com/myblog as domain), WordPress Migrate's curl functions won't be able to write the destination file and fail.

From what I can see, the only thing that's missing is directory creation under the wordpress:// path; if I manually create the example.com directory (under sites/default/files/wordpress/example.com), file is properly written.