Language segment is added to cross-site URLs when selecting automatic language

Description

Steps to reproduce

1. Create 2 sites, one in English and one in Swedish.
2. Make sure both are mapped to a host name.
3. On the Swedish site, create a link from a LinkCollection property, leave the Language as "Automatic (Default)" and create a link to the English site.
4. Go to view mode and view the link.

Expected: http://englishsite/ (works)
Actual: http://englishsite/sv/ (causes 404)

Alternative repro

1. Enable Swedish and English on a site and make sure the start page is translated.
2. Create a Swedish page and a English page using page type Standard (or any type with an XHTML editor).
3. From the English page, create a link to the Swedish page using "Automatic" language in the XHMTL editor.

Expected: The link goes to the Swedish page/site.
Actual: The link does not work (you get 404).

Workaround: Specify the language when making links to content that does not exist in the language you are linking from, or add fallback rules in edit mode.