Drag and drop image into TinyMCE not working when on an URL that is not connected to a site

Steps to reproduce

When accessing edit mode on an URL that is not defined as a site in admin mode (under Manager Web Sites). Then drag and drop of media causes broken images on the site.

For example if you have a alloy demo site, with url http://machinename:17000, machine name with port, and you browse to the site using http://localhost:17000.

And insert a image into xhtml, using drag and drop from asset panel.  The image url will be like:

http://localhost:17006/secure/CMS/Content/globalassets/en/alloy-track/alloy-track-video/preview.png,,156?epieditmode=False

The editor does not see that this is wrong, since they are logged in, and have access to /secure/cms/content. But when you are not logged in, you do not have access to the url ,and the image does not show.

Steps to reproduce

- install a alloy site with standard url(host name) like machine name and a port

- navigate to the site using localhost and the port.

- go to edit, drag a image from asset panel into tinymce.(mainbody)

- publish and then go to view mode, not logged in.

- You then do not see the image.

Root cause: The current behaviour expects the host name to be mapped to the current site, if possible it should not use host names in drag and drop.