BigTextFields: Cross-references are not removed from the jahia_link table

Cross-references (hardcoded links) are not removed from the jahia_link table if they are removed from the BigText field.

1) Create e.g. a main_content container and add a link (in the FCKeditor) to any validated page (say 'Target').
2) Validate current page (say 'Source')
3) Open Update Container engine for the main_container and edit BigText field, removing the link to the 'Target' page (just remove the whole BigText field content)
4) Validate the 'Source' page
5) Try to delete the 'Target' page --> warning is shown that there is still a cross-reference to it