Advagg hook_requirements() don't work if self-site not directly accessible

Advagg reports a number of failures when it can't access itself via http. For example, an http server for "example.com" might for *many* reasons not be able to access http://example.com: The most common are that the network infrastructure of the server has a load balancer or something in front of it, which cannot be accessed from inside the network using the external IP. But there are many reasons this can happen.

However advagg naively reports quite a number of problems when the site can't access itself:

* Several 404 fails (which can in fact be turned off with $conf['advagg_skip_404_check'] = FALSE;) These could be a lot smarter if they realized that an http response of 0 was a signal.
* "Adv CSS/JS Agg - If-Modified-Since"

The If-Modified-Since header is being ignored by your web server.
The web servers configuration will need to be adjusted. The server should have responded with a 304, instead a 0 was returned.
* Possibly "Adv CSS/JS Agg - gzip"	Gzip is failing for css files. The web servers configuration will need to be adjusted. In most cases make sure that the webroots .htaccess file still contains this section "Rules to correctly serve gzip compressed CSS and JS files".

(Note that the code could be much smarter, understanding that a 0 was complete failure)

Is there a workaround for this problem? Since this excellent module is deployed in many production environments I'd expect to see a lot of complaints about the noise generated on admin/reports/status, but I don't see it on a casual review of the issues.