[FIX] html_sanitize: partial backport of trunk revision 5047.
Unescape elements that have been wrongly escaped.

Some elements (eg: 'href' tag in links) are sanitised in templates which prevents the execution of mako templates.
[MERGE] [FIX] html_sanitize: partial backport of trunk revision 5047 (opw 603452).
Unescape elements that have been wrongly escaped.

Some elements (eg: 'href' tag in links) are sanitised in templates which prevents the execution of mako templates.