Translations override the document in the default language

Problem raised by the following scenario:

1. edit an existing document in a multilingual XWiki
2. hit a language link for translating it
3. save it: the saved document will override the document in the default language

Commenting out the change r4858 in EditAction.java fixes this specific issue (http://fisheye2.cenqua.com/browse/xwiki/xwiki-platform/core/trunk/xwiki-core/src/main/java/com/xpn/xwiki/web/EditAction.java?r1=4719&r2=4858)